Getting more power in a C body

[Norwegianmopar]

For those of you who have C bodies with a bit more than stock power, what setup do you have?

Did you beef up the stock 383 or 440, build a stroker or use an injection kit like Holly Sniper?

The stock 383 2bbl will probably need a rebuild at some point down the road and I would do the trans to if so. Might look to get a done engine and trans and rebuild the original later on.

I like the 2,76 rear end tbh due to the comfy rpm at highway speeds so we would probably want a torque monster more than a high HP "musclecar engine". Gas milage counts too, right?

I am pretty sure this big old lady can get decent performance with the right setup. She already has the stance of a musclecar

All experience and input is highly appreciated.

 

[71Polara383]

Good dual exhaust
Dual plane intake.
Properly tuned carb or EFI
Proper timing, between 12-14 initial seems to be the ticket with big blocks I've messed with.

Going further...

A valve job with oversized valves would be beneficial. I'm guessing you have 516s and small exhaust valves.
Street/Strip Camshaft around .500"
10" Torque converter to match the camshafts power band
Lastly, 3.23 or 3.55 gearing. That would give you better off the line performance and feel, without compromising highway driveability completely...

These cars aren't too much heavier than the Muscle cars and can be hopped up to run with them. Just depends on what you want to do and your main purpose for the car.

 

[MEV]

I had the same dilema, i went the 505/512 stroker 440. Its funner' than stomping baby chickens!

 

[Norwegianmopar]

Good dual exhaust
Dual plane intake.
Properly tuned carb or EFI
Proper timing, between 12-14 initial seems to be the ticket with big blocks I've messed with.

Going further...

A valve job with oversized valves would be beneficial. I'm guessing you have 516s and small exhaust valves.
Street/Strip Camshaft around .500"
10" Torque converter to match the camshafts power band
Lastly, 3.23 or 3.55 gearing. That would give you better off the line performance and feel, without compromising highway driveability.

These cars aren't too much heavier than the Muscle cars and can be hopped up to run with them. Just depends on what you want to do and your main purpose for the car.

I have been playing with the idea of maybe getting a done engine and trans (with extra cooler) and just put aside the original ones for a later rebuild. A 440 would probably be the best choice considering cost vs power. A stroked 440 would be even more fun.

We don't want it to behave like a choppy musclecar, but rather have the best of two worlds - a comfy cruiser but with enough power to mess with the street brawlers if "needed".

Decent gas milage and rpm at highway speeds counts too since gas is pretty expensive here in Norway (3-4 × US cost).

I have also thought about this car not being that much heavier than a B body so it should be able to get pretty good performance if wanted.

 

[71Polara383]

Honestly. If we're talking about full on engine swaps here with the goal of performance and mileage in mind...I think these days the best bang for your buck will be finding a 5.7 or 6.4 Hemi/8speed combo.

For about what you'll spend on an old iron block build with new parts/machine shop costs and time...you'll practically be at the cost of a used drop out.

 

[13b Bro]

I had the same dilema, i went the 505/512 stroker 440. Its funner' than stomping baby chickens!

 

[CBODY67]

For the ultimate 4500lbs the car and passengers might weigh, a "torque motor that rpms" might work better. All of that max horsepower people like to brag about only happens above 5000rpm, not at 2800rpm cruising speeds (which should be above 80mph on the Interstate). So the dual exhausts can aid that, too. As can the desired 4bbl and such.

Which then makes cam selection a key item. Lots of valve lift need ports which will support that lift AND make great flow at those lift numbers. Adding the 1.74" exhaust valves (with hard seats, anyway) can help, but probably not as much as some might suspect. Just my gut suspicion. Use 1.6 rocker arms NOT to increase effective valve lift, but to get the valve off of the seat quicker for more flow sooner, only.

If you have the earlier closed chamber heads, add the larger exhaust valves to match the 1967 GTX 440/375 heads. If you have the later open chamber heads, add some quench dome pistons to replicate the closed chamber heads with more "quench pad" for a more active mixture motion in the chamber.

Check and see if Mahle builds some pistons for 383s, which have the modern "MM Ring Package", which can unlock some additional power via decreased friction from the thinner rings. Their pistons come with the rings installed, too.

If you decide on EFI, you'll need a distributor compatible with the system, so you might as well get a EFI system that also controls ignition advance functions, too. If not, a good electronic ignition kit from Rick Ehrenberger's eBay store might work well.

Personally, I like the relaxed highway cruising orientation, with 3000rpm being about 85mph or so. Yep, might not be as quick off the line, but with enough guts to lay some rubber, though. With can support my orientation of "a torque motor that rpms".

Transmission, get a full rebuild kit from a noted transmission builder/vendor company. Frictions with a bit more "bite", the "high ratio" lever, new "steels", a 4bbl governor, and the 10.75" torque converter (for a little bit more stall speed, but still "tight" by highway speeds).

Just some thoughts,
CBODY67

 

[CBODY67]

The Gen III Hemi is a viable option, with the 8-spd ZF behind it. Then you'll need the electronics to run them, though. PLUS a deeper rear axle gear to support the OD gears in the transmission. Or possibly a beefed LA-engine 727 transmission so you don't need the rear axle gears or trans controller or expensive adapter to put it with a 727.

Note: The OP is in Norway, so options of available salvage yard parts are more limited than in the USA. "Some shipping required" for things we can drive to and get in the USA. FWIW

Whatever works,
CBODY67

 

[Just Carbs]

Cubic inches. And keep the trans and rear gear.

 

[Norwegianmopar]

For the ultimate 4500lbs the car and passengers might weigh, a "torque motor that rpms" might work better. All of that max horsepower people like to brag about only happens above 5000rpm, not at 2800rpm cruising speeds (which should be above 80mph on the Interstate). So the dual exhausts can aid that, too. As can the desired 4bbl and such.

Which then makes cam selection a key item. Lots of valve lift need ports which will support that lift AND make great flow at those lift numbers. Adding the 1.74" exhaust valves (with hard seats, anyway) can help, but probably not as much as some might suspect. Just my gut suspicion. Use 1.6 rocker arms NOT to increase effective valve lift, but to get the valve off of the seat quicker for more flow sooner, only.

If you have the earlier closed chamber heads, add the larger exhaust valves to match the 1967 GTX 440/375 heads. If you have the later open chamber heads, add some quench dome pistons to replicate the closed chamber heads with more "quench pad" for a more active mixture motion in the chamber.

Check and see if Mahle builds some pistons for 383s, which have the modern "MM Ring Package", which can unlock some additional power via decreased friction from the thinner rings. Their pistons come with the rings installed, too.

If you decide on EFI, you'll need a distributor compatible with the system, so you might as well get a EFI system that also controls ignition advance functions, too. If not, a good electronic ignition kit from Rick Ehrenberger's eBay store might work well.

Personally, I like the relaxed highway cruising orientation, with 3000rpm being about 85mph or so. Yep, might not be as quick off the line, but with enough guts to lay some rubber, though. With can support my orientation of "a torque motor that rpms".

Transmission, get a full rebuild kit from a noted transmission builder/vendor company. Frictions with a bit more "bite", the "high ratio" lever, new "steels", a 4bbl governor, and the 10.75" torque converter (for a little bit more stall speed, but still "tight" by highway speeds).

Just some thoughts,
CBODY67

A torque monster that rpms is a very good definition on what I want it to be. Not looking for a street legal race car by any means, but rather a cruiser with some "hidden power" when called upon.

The trans will have to match it for sure and we might get an extra oil cooler for it as well since we are dreaming about maybe getting a trailer hitch and use it to pull a camper in the summer.

We plan to use this car a lot and therefore will upgrade the interior too to get it a bit more comfy (better support in the front buckets when redoing the interior).

It already handles quite nice with all new suspension and the front disc brakes are really good with no pulling to either side whatsoever under hard braking.

Yes, a newer 5,7 or 6,4 Hemi with accessories would be fun, but availability and build cost might not be...

 

[Norwegianmopar]

Cubic inches. And keep the trans and rear gear.

"There is no substitute for cubic inches" is a mantra I like, so yes that is what we would prefer over any high rpm horsepower setup. It is a cruiser first and foremost, but a little extra ooomphh wouldn't hurt...

 

[Just Carbs]

For heavy go-fast boats we generally go with 572 cubes and 2 to 8 pounds of boost.
If I was "really" set on making a C body move it would be a big motor and a centrifugal blower.
It's the best bang for the buck if a lot of all-day everyday power is necessary.
We know, because we blew up a lot of fancy motors racing boats.
Very impressive torque in the factory rpm range. About twice factory power.

 

[71Polara383]

Yes, a newer 5,7 or 6,4 Hemi with accessories would be fun, but availability and build cost might not be...

Once you start adding up the cost of setting up a big inch 440 build and compare it with used hemi drop outs with some wiring/computers included... you'll see the gap in cost is closer than you'd think.

Also no steeper gears really needed with the 8speed, they are available with a 2.62 or 3.09 ratios, so 2.76, 2.94, or 3.23 would all work well.

 

[furious70]

If mpg truly matters, the gen III hemi wins.
Build costs of a stroker and 727 will be in the same ballpark when you consider the headers and carb and such

 

[live4theking]

Unrelated curious question. What is this on your wall?

 

[Norwegianmopar]

Unrelated curious question. What is this on your wall?
View attachment 674172

Brake tester, shows the brake power on each wheel.

 

[Norwegianmopar]

Any experience with the 383/496 stroker kit?

Stroker Kits-store.440source.com

 

[496 polara]

Good dual exhaust
Dual plane intake.
Properly tuned carb or EFI
Proper timing, between 12-14 initial seems to be the ticket with big blocks I've messed with.

Agree with that 100%

No matter what engine size you end up with a better flowing set of heads makes everything easier. Doesn't really matter whose name is on them(Edelbrock,sidewinder,440 source,etc).
Long tube headers (or shorty headers) with no larger than 1 3/4 primary tubes.
Camshaft in the 220's @ .050 for a stroker with 2.76 gears.

My old 70 Polara ended up with a 496 c.i. stroked 440,well ported factory iron heads with large valves,a small solid cam,1 3/4 hooker super comp headers and 2.5 dual exhaust. Edelbrock ch4b intake and holley 750 vacuum secondary.
Ran 12.54 in the 1/4 mile with 3.55 gears. For 2.76 gears a smaller cam and would not have changed much else.

 

[MEV]

Remember, i drive this car year round, i just drove it to work this morning, 30 miles one way. I drive it to the drag strip 80+miles one way, and i take the girlfriend out tofancy dinners in it. It makes all the gals at the lodge jealous. It has great throttle response, tons of torque and plenty of horsepower.