performance 1966 chrysler newport

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i have a 1966 chrysler newport convertible that i want to turn into a fast full sized muscle car and there’s a few things i’m thinking about.

how much weight reduction can i do and still have it look stock, im thinking fiberglass panels but id like to keep the interior as stock as possible

and what ways are there to fit wider rims, anything bigger than a 7 would rub i’m wanting around 10 inches wide to fit
 
First reaction to your request would be something of a lack of knowledge of UniBody cars without a top on them. For a normal car with their OEM engines, they were fine, but when you start to talk about "big power" and "muscle car", that can imply a car with a lot of torque from the motor and/or drivetrain. On a full-frame car (as in Ford or GM), no big problem, but in a UniBody car, much more issues with body flex and such, which can be made worse by "muscle car" equipment (in the current definition of "muscle car").

It's my understanding that B-body convertibles, as in Coronet R/T, all were prone to "coach joint" separation where the quarter panel and Dutchman Panel (panel between the quarter panel below the rear window), as in cracked from body flex. No reason to suspect a C-body would not be different.

There are threads in here on "How wide of a tire . . . ", so that's searchable.

Weight reduction? No fibreglass panels ever existed for Chryslers, that I ever knew of, then or now. ONLY things where weight reduction might happen would be the hood and deck lid, as the front fenders, doors, and quarter panels (which are welded on) are considered to be a part of the basic structure. There MIGHT be a replacement front stub frame, that can include coil-overs on the front and rack and pinion steering in one feld swoop. Not inexpensive, though.

One side issue is the generally low production rate of ANY Chrysler-brand convertible, which makes it rare to start with. Many Newports were probably "used" and discarded "as cars", whereas a similar 300 might have a better chance of surviving (due to its more upscale customer base).

Now, what you CAN do and has been done . . . a Gen III Hemi and ZF 8-speed powertrain swap. Contingent on getting a trans controller for the ZF automatic and electronics to run the Gen III Hemi engine. Since the latest thread in here on that, I believe that transmission controllers have come to market? In order to use the top OD gears in the ZF, might need a 3.55 rear axle ratio.

Otherwise, a 383 stroker motor with a good TorqueFlite rebuild can be good. That would keep your existing architecture but with more power and performance.

Suspension? Some good HD shocks, updated steering gearbox, and maybe an upgraded front sway bar mechanism are available. Threads in here on those things.

Add some 17" VN501s with something like 245/45x17 Comp TAs to keep the tire OD basically where it was with the stock tires on it but look better with "modern rubber" on the ground.

Factory radio upgrade? Aurora Designs/Gary Tayman, et al, can provide modern upgrades for that.

Bench seat interior? You can either go back with stock-oriented vinyl or cloth or do something a bit different. Your judgment call.

When your car was new, a "muscle car" was generally any car, like a Plymouth Belvedere, Dodge Coronet, or similar-sized GM and Ford products, that had a "big car" big engine in it. In the case of Plymouths and Dodges, those "big engines" usually came from Chryslers, with a few things added for a bit more horsepower. 5000rpm max horsepower, with lots of lower-rpm torque.

Although they had very ample power, the C-bodies were not really termed "muscle cars" in the same orientation. They were "too big", "too heavy", and such. The 600lb lighter B-bodies fit the bill better.

Now, there is one member in here that has a '66 New Yorker 4-dr with a 500"+ stroker motor, with WIDE tires all around, that runs 13 second quarter miles (a few YouTube videos, as I recall). But that is a "closed car" with a roof, plus other underbody "things" to make the wide tires fit and look stock, until you see the width.

And, of course, check out the threads in here on "Ammeter Bypass"! Several of them.

Enjoy!
CBODY67
 
Don’t worry about making it lighter, it will be a huge ordeal and gain you very little. These cars are about the same weight as a modern charger/challenger so not a huge deal. Read up on making mopars handle with stock suspension. The same stuff that works on the smaller cars works on the bigger cars. There are several companies that make torsion bars, sway bars, leaf springs, etc. You can likely run modern tires on 8 or 10 inch wheels with the proper backspacing since lo-pro tires don’t have the sidewall bulge of taller aspect ratio tires.

From there, figure out what drivetrain you want to make the car do what you expect the car to do. You don’t need to go clean sheet to make these things very good, just do some research. Don’t get discouraged at finding very little info, or getting pushback on this type of thing. Big Chryslers aren’t Camaros or mustangs, you will need to figure some things out on your own. You likely will find very few absolutes about what will work since most in this segment aren’t doing what you want to do. Do your research and have at it.
Travis..
 
I wouldnt even attempt to lighten it....if you`re building a full on race car, you wouldnt be asking questions here. Just consider some bolt on mods.... cam, converter and tall rear gears.....go have fun. Then someone can change it back if you get bored with it.
 
Our heavy cars need a lot of traction, good tires are essential.
no matter what car, matching the cam, converter and gearing is essential to making a car quick.
 
I have addressed the rear tire situation on a 66 Newport by simply moving the leaf springs into the frame rails. The wheel wells on these are fairly large and will accommodate a much larger tire without mini-tubbing or cutting any metal once the leaf springs are moved inboard. Agree with previous posts regarding weight reduction, not really much you can do other than things like newer disc brakes or aluminum heads on the engine (which would obviously get you more hp also if done right).
 
You can safely fit an 8x15 wheel with a 225/75r15 tire. As other have said the unibody is going to be the weak point. You should be thinking about subframe connectors and strengthening if you are going to make real power.

As soon as you make any power or if you feel like driving hard with a stock motor you are going to quickly learn about the wild amounts of body roll these cars will have. I just finished installing all new stuff from Firm Feel which made the car handle significantly better. Get all the big stuff and poly bushings. You won't regret it.

As far as power goes: Its a Chrysler big block. There is endless aftermarket and you have the largest engine bay they came in. This is also your opportunity to cut weight. Aluminum heads, aluminum intake, aluminum water pump housing, etc. That's already a whole American worth of weight you just dropped!

If you want to do something really cool (what I'm doing), you can also put a T56 behind that big block and get two overdrive gears. That means you can bump the diff ratio a good bit without losing your high speed. You can also leave the 2.76 and have people here tell you you are making bad choices. You should be able to barely get it into 6th around 130...
 
Here's a thought. Just don't do it. It's not practical. Especially being a convertible. The power required to move that much weight could possibly ruin the unibody with all the hidden rust. If the car is clean, why destroy it by altering panels & stuff. Find something else like an old B body maybe a challenger. They are still out there.GOOD LUCK.
 
Looks like he didn’t like what he heard. If he’s been back to read the responses, he wasn’t logged in. He joined on Monday, started this thread, and logged out an hour later never to return.
Travis..
 
Over the years of being in forum as this, I've observed that some new posters can come in with questions about "making their car better". No problem with that. But when the "better" questions relate to powerful engines or wide wheels/tires, that can put a few different dynamics on things, as to their desires, orientations, and possible "influencers" (whether a social group they might desire to identify with), online or otherwise.

Which can also relate to particular age and "automobile knowledge" demographics. Not really understanding the different construction techniques between a UniBody Chrysler product or a similar model Ford or GM vehicle. Nor possibly being aware that a UniBody convertible can be a different breed of car from a body/frame convertible. Or the rarity of any Chrysler C-body convertible, especially a Newport.

To me, the posts which relate to "I want to get rid of those torsion bars so I can put headers on my car" really tend to pin-point the posters' priorities or not knowing what's really "out there" as to parts and pieces. Might not be the desired long-tube headers specifically for C-body cars, per se, but "headers" are available for C-bodies, just at a higher price. Or the even higher price for a pair of headers built out of U-bend components.

Then when forum members seek to "impart knowledge", the OP takes that as "unhelpful" (as it's not what they want to hear"), and vanishes. Oh well . . . perhaps they'll encounter others in their quest which might tell them some of the same things? OR perhaps the "school of hard knocks" might hand them a diploma?

Take care,
CBODY67
 
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I’m of the mind that it’s his car to do with as he likes, it’s not a hemi Cuda or anything. I can tell he’s green, but when you want to do things to your vehicle that are out of the norm of the regular demographic, you need to forge your own path. There aren’t many people with “muscle car type builds” in the c body world, and less that seem to be documented on forums. with the relative affordability of these cars over the more mainstream muscle, we need to expect to see more and more of these cars being modified. I say have at it, but a guy needs to be willing to step out on his own to get it done. There is no set blueprint like the popular cars.
Travis..
 
Looks like he didn’t like what he heard. If he’s been back to read the responses, he wasn’t logged in. He joined on Monday, started this thread, and logged out an hour later never to return.
Travis..
No surprise there. Old folks are often upset that kids don't join the hobby then treat kids that want to do kid stuff like crap. I joined a Facebook group "Ratty C Body Muscle" that seems to have everyone who would be chased off of here.

Pretty much every thread where someone wants to change their C body away from "exactly stock" here is met with a list of people who have never actually modified anything telling them why its a bad idea.
 
No surprise there. Old folks are often upset that kids don't join the hobby then treat kids that want to do kid stuff like crap. I joined a Facebook group "Ratty C Body Muscle" that seems to have everyone who would be chased off of here.

Pretty much every thread where someone wants to change their C body away from "exactly stock" here is met with a list of people who have never actually modified anything telling them why its a bad idea.
My late machine shop operative, back in the 1980s, had a poster on his office door, "17 Year Olds, Leave Home NOW While You Know Everything".

Modern "17 Year Olds" can still be the same now as then, ONLY thing is that we who used to be that young, have lived with these cars from when they were "just used cars", or even new cars, and have learned many things about them. Including "why" some things/modifications are "bad ideas". Not specifically that they'll "ruin the cars", but because they just don't work the same as the same thing might on a GM or Ford car of similar size.

I also suspect they have not spend thousands and thousands of miles on the road in these cars to feel what makes them different than a similar GM or Ford vehicle. In one area, like how responsive the suspension reacts to steering input, rather than the numbed feeling of Ford power steering, for example.

These modern 17 year olds have grown up in a car culture where all new cars are pretty much the same, with struts rather than shocks, plus coio-overs OEM on pretty much everything. When our C-body cars were new, those things were not around or common. They have yet to experience any new vehicle with the degree of body flex even the UniBodies had, either.

Perhaps OUR message might be "Learn about the cars FIRET. How they work and why as each OEM did different things back then, rather than being as standardized and "the same" as modern vehicles tend to be, BEFORE you start changing things"?

Perhaps there can be some "life lessons" in the mix, too? Like YOU don't have to do what some Influencer claims you need to do to your car to be cool or "fit in" with a particular group of "friends"? They ALSO need to understand that many in here were once young like then and might have wanted to do some of the same things to our cars back then. Only to find out later that it was a bad idea after the new had worn off of the changes. Only real difference is that WE had trusted individuals we could talk to, rather than somebody on electronic social media (who might be "as green" as they are). WE knew what "No" or "That's not a good idea" meant. Apparently younger versions of "17 Year Olds" don't yet understand that?

To me, it's no surprise to see a group on Facebook who might not like what "old foggies" have told them about various modifications. Those people are just looking for validation of their desires, no more, no less. Apparently they have found a place for that? Perhaps they can all learn together? If they accomplish their goals, they should be congratulated.

I'm glad they have the energy and funding to achieve their dreams, or discover there might need to be a different route to them.

This group might be "tough", but I've seen others which are much tougher on people who might desire to alter their vehicles. People who will spend massive amounts of money to keep their engines completely stock, rather than spending less on them to get something newer and better-performing, even if it might take some tweaking to make it work its best.

Enjoy!
CBODY67
 
My late machine shop operative, back in the 1980s, had a poster on his office door, "17 Year Olds, Leave Home NOW While You Know Everything".

Modern "17 Year Olds" can still be the same now as then, ONLY thing is that we who used to be that young, have lived with these cars from when they were "just used cars", or even new cars, and have learned many things about them. Including "why" some things/modifications are "bad ideas". Not specifically that they'll "ruin the cars", but because they just don't work the same as the same thing might on a GM or Ford car of similar size.

I also suspect they have not spend thousands and thousands of miles on the road in these cars to feel what makes them different than a similar GM or Ford vehicle. In one area, like how responsive the suspension reacts to steering input, rather than the numbed feeling of Ford power steering, for example.

These modern 17 year olds have grown up in a car culture where all new cars are pretty much the same, with struts rather than shocks, plus coio-overs OEM on pretty much everything. When our C-body cars were new, those things were not around or common. They have yet to experience any new vehicle with the degree of body flex even the UniBodies had, either.

Perhaps OUR message might be "Learn about the cars FIRET. How they work and why as each OEM did different things back then, rather than being as standardized and "the same" as modern vehicles tend to be, BEFORE you start changing things"?

Perhaps there can be some "life lessons" in the mix, too? Like YOU don't have to do what some Influencer claims you need to do to your car to be cool or "fit in" with a particular group of "friends"? They ALSO need to understand that many in here were once young like then and might have wanted to do some of the same things to our cars back then. Only to find out later that it was a bad idea after the new had worn off of the changes. Only real difference is that WE had trusted individuals we could talk to, rather than somebody on electronic social media (who might be "as green" as they are). WE knew what "No" or "That's not a good idea" meant. Apparently younger versions of "17 Year Olds" don't yet understand that?

To me, it's no surprise to see a group on Facebook who might not like what "old foggies" have told them about various modifications. Those people are just looking for validation of their desires, no more, no less. Apparently they have found a place for that? Perhaps they can all learn together? If they accomplish their goals, they should be congratulated.

I'm glad they have the energy and funding to achieve their dreams, or discover there might need to be a different route to them.

This group might be "tough", but I've seen others which are much tougher on people who might desire to alter their vehicles. People who will spend massive amounts of money to keep their engines completely stock, rather than spending less on them to get something newer and better-performing, even if it might take some tweaking to make it work its best.

Enjoy!
CBODY67
My experience is more a list of people telling me why whatever I asked about is a "terrible idea" any all the reasons I'll hate it and sell the car. Then one guy who has actually done the thing I'm asking about come along and tells me it'll be a great time. Feel free to look at my post history for examples.

My Newport was my first car in 2013. 90,000 miles later, I just drove it on a 2,000 mile roadtrip two weeks ago after doing all the things everyone here told me I'd hate (In this case stiff suspension from Firm Feel along with Poly everything). Turns out they were all wrong and the car handles better than ever. I was also told not to put AT tires on it. They're great.

There have been a couple decent posts here with actual information on what you can do to a body such as the one about moving the leafs in, and me recommending subframe connectors. Sure, every kid starts off thinking they're gonna make grandpa's car into a 6 second drag car, but you can steer them straight without telling them their car is weak and unable to handle a couple more horsepower while offering no actual advice.


The first bit of advice I ever got from a "knowledgeable" person after getting my Newport was "That's a good car to get rid of. Sell it to a derby guy and get something worth working on."

I've spent the last decade ignoring people like him and have had a great time.

People who life different things than you might actually just like what they are doing. It doesn't have to be about influencers, validation, fitting in, or whatever else "the kids these days" are doing. You may be surprised to learn the "kids" today don't use Facebook at all because its "for old people". I've talked to plenty of "trusted individuals" who have told me all sorts of hogwash. It turns out a random guy in a barn isn't any more or less knowledgeable than random guy online. The difference is the old guy in a barn won't have anyone read what he is saying and point out the flaws.
 
The big difference is that so many more people were doing so many different things to so many different cars in the 70s. A lot of it was the same old stuff that was known to work, a lot of it was new stuff that worked, or didn't work. And all of it right there to see firsthand. There was a lot more exposure to everything back then.
Just the upper middle-class street alone I lived on in 1974 had at least a dozen altered cars. Ford, GM, Mopar, AMC. From simple dual exhaust to cross breed engine swaps.
I can see why the youngsters don't know what's compatible with what.
I can tell you that a Porsche 911 benefit's greatly from a 1966 Olds Toronado 425 drive train. That car definitely did fly in the face of trying to get a big car to go fast.
 
The big difference is that so many more people were doing so many different things to so many different cars in the 70s. A lot of it was the same old stuff that was known to work, a lot of it was new stuff that worked, or didn't work. And all of it right there to see firsthand. There was a lot more exposure to everything back then.
Just the upper middle-class street alone I lived on in 1974 had at least a dozen altered cars. Ford, GM, Mopar, AMC. From simple dual exhaust to cross breed engine swaps.
I can see why the youngsters don't know what's compatible with what.
I can tell you that a Porsche 911 benefit's greatly from a 1966 Olds Toronado 425 drive train. That car definitely did fly in the face of trying to get a big car to go fast.
This in the type of environment that breeds "daddy taught me" knowledge I see today from people of that era as well as their children. Sometimes its true, Sometimes it isn't but across all of it they never seem to have the underlying knowledge of why they are doing what they are doing. The "youngsters" have access to, as well as the skills to use a huge wealth of knowledge from the internet.

I don't have to see what rich Bobby down the road did and copy him. I can read up on how someone on the other side of the planet did it, contact them and ask a few questions, then go to my (online) mechanical engineer / math buddy and have him run the math to make sure my ideas can be done safely, actually do it, then go back to each and share the results.

I think too many people here fall into the " I didn't do it so it must be bad" trope which causes new people to stay away. Luckily I didn't ask anyone here before I bought my Newport because I'd have steered clear if some dope told me I'd crack my C pillar in half if I put better heads on it. Now I know that if I make too much power I'll have to brace it but that's an actual helpful; answer rather than "don't try".


Entertainingly I've seen about the same arguments about what would happen if you put a big power v8 in a Porsche.
 
I'll admit that "terrible idea" has a variety of meanings. From VERY terrible idea to "little bit" terrible idea. With a normal "bad idea" in the mix, too.

IF somebody tried to steer me away from doing something I'd read about, done on other cars, then I'd start doing research to find out why I was told that. THEN after doing my research, over time, I'd know why I was told that, possibly even discovering something better in the process. Research which included going to the popular car cruises, looking at cars, what had been done to them, and talking to the owners about their modifications. Noticing their tone of voice when talking about their modifications, in order to detect their enthusiasm with what they'd done, or otherwise. Then I'd also observe when they left and how the modifications affected how the car acted and drove off.

The Saturday and Sunday morning "Power Block" programming proved that "anything is possible", IF one has decent fabrication skills, backed by a shop full of metal breaks, welders, and cutters, among other things. NONE of it inexpensive, either. When many of us were 17 year olds, that sort of thing was usually only in race shops, to build race car chassis, bodies, and such. Places waayy above my capabilities to pay for.

One of the best riding/handling cars I ever drove was a friend's '71 'Cuda 383 with the optional HEMI suspension under it. A suspension which the magazines recommended against as it was "harsh". With its less sound deadening, it was quieter than our then-new '72 Newport Royal. There was one sweeping turn that had a washboard section to one side. My '66 Newport with HD shocks would side-step a bit on it, but that 'Cuda drove right through it smooth and flat, as if it was not there.

Body flex can be tricky. In the body design, there are some areas which are stronger to counter-act such flex, as others are designed to absorb it. Doing additional stiffening, up front, can do a lot to prevent later expensive repairs. I also DO know that Chrysler designs better UniBody cars than GM does, especially compared to the GM F-body Gen II Camaro/Firebirds. A friend noted "F-body" means "Flex Body". Sub-frame connectors are the norm on those cars if engine power and torque is increased very much. Not to mention on T-top cars. Sub-frame connectors would also benefit normal HD suspension cars, too. On my '77 LT, I also added all of the front sub-frame reinforcements to it, which did help steering feel a bit.

"AT tires", with their truck-chassis orientation, provide tire sidewalls which are stiffer than what we had back then. Tread designs and rubber compounds are better, too. They might look "different", but can be an incognito "performance tire" where normal perf tires are not built in that size anymore. Just have to get past the cosmetics on the sidewalls.

Weight removal can always signal a red light when a UniBody convertible is the car it is desired for. Convertibles already had stiffening in the floor pan to counter act the loss of the metal roof. The ONE exception was the '58-'60 T-birds, where a hradtop could be removed to make it into a convertible, with no additional stiffening needed as Ford over-designed that UniBody such that such was possible. As mentioned above, the best way to reduce weight in a Chrysler convertible is aluminum engine components (i.e., cyl heads, intake manifold) and even tubular exhaust headers. Only the very serious drag racers of the middle 1960s era "lightened" their cars (with acid-dipped fenders and a bit of Swiss cheese action), but then THEY had ready access to the OEM body designers to discover WHERE they could do that and not affect body integrity. Additionally, those cars were "throw-aways" rather than needing to last well past 100K miles on normal city streets and rough country roads.

The BAD thing about body flex is that it takes so long to appear, many times. Stiffen one part and the flex that part/area was supposed to absorb is transferred to a place that was not designed to deal with it. Which can then result in metal flex-breaks that must be repaired. Such breaks might be more prone on a non-C-body car because the C-body cars have more wheelbase length to absorb such flex than a smaller body vehicle does?

There is ONE thing I would recommend that ANY Chrysler Corp vehicle enthusiast do BEFORE getting involved in modifications. That is to attend the Mopar Nats and look at what others have done. It IS very possible that what one might be considering is there, so you can talk to the owners and find out what it took to do what they did (and you are considering doing). Plan on going for about five years straight, as what's there can change yearly.

It was at Mopar Nats that I discovered how deceptively EASY it was to put a B/RB engine in a '79 Dodge St. Regis/Chrysler Newport. In this case, the car started as a genuine police car (with factory dual exhausts). Only thing that had to be fabbed was the a/c line from the RV-2 compressor to the condenser. Everything else was "salvage yard" stuff. No chrome, just paint under the hood. Plus a LA-motor pie pan on a factory dual snorkel air cleaner. A great Malaise-era sleeper! He told the Chevy guys it was a 318, as they didn't know any better, except in a few cases.

One year, there was a high school auto shop class there with a 4-dr K-car. The car looked great in every nook and cranny I could see on the grass show field. The paint was "custom", but flawless. The custom interior was flawless. EVERYTHING was flawless. INCLUDING the Suicide Doors for the rear doors! Obviously, I suspect they took a worn-out car and completely remanufactured it, but added lots of things to replace the "stock" things in the process. Investing a huge amount of money in the process, but with a final product that was stunning and outstanding in the process. In many ways, "a terrible idea", but something that was totally unique and was an effective showcase for the skills they would use in the future to earn a living with. Their pride in the car was very evident as they prepped it for judging and made it look great. This was in the 1990s.

The ONE thing I really liked about the Mopar Nats was its INTERGENERATIONAL aspect. Lots of younger people with their cars, as there were grand-parents there to keep their grandkids while the parents were off searching for parts, cars, and other things. One year, I saw such under the Viper tent. By the convenience store near the end of the drag strip, I watched a high shcool guy put slicks on the front of his upgraded K-car, with a torque wrench, as his father AND grand-father watched nearby. I had never seen such at the many other non-Mopar events I'd ever attended!

When and if you do go to the Nats, BE IN SHAPE to be able to walk all day, non-stop, and then come back the next days and do it again. In 90 degree F heat and some damper humidity in the mornings. It WILL be enjoyable!

Enjoy!
CBODY67
 
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