Will a purpose made dual exhaust for a '67 C body work on a '66?

[Gerald Morris]

That's plenty of clearance.

The factory's design, at least as interpreted by Maremont when they made all these pipes, also comes real close to the driveshaft on the one side but I've never had it hit.

THANK YOU GENTLEMEN! Never having done anything like this before, I simply lack knowledge from experience. The pipe isn't as close as a 2 dimensional picture makes it appear either. I noticed a big thick lateral strap on the original 1 pipe installation too, so I think having a little lateral bracing for this work will only help keep things firmly where they should be.

Again, thank you both for setting my mind at ease. I don't relish crawling under that metal in temperatures considered lethal if in a fever. What little "trimming" work I want to do can WAIT until AUTUMN!

 

[Gerald Morris]

Update: Its been over 3 weeks with these pipes now and the engine DOES run with improved gas mileage for going from a single pipe to 2, doubling the cross sectional area for the exhaust gas to escape the heads. City mileage now is 11 mpg, instead of 10. I yearn to take Tilly on the interstate, likely to Casa Grande to look for parts. I got ~14.5 mpg on a similar run 4 yrs ago, so we shall see how she does now, with the small improvements and repairs made since then.

 

[oldkimmer]

Have u did a timing curve on Tilly yet? That can sure help. Kim

 

[Gerald Morris]

Have u did a timing curve on Tilly yet? That can sure help. Kim

I plan to gather my data points for a good curve this Fall, when it chills down to just 90 F or so here, likely November. I too am itching to know how well this distributor follows OEM spec, or not. Been running at 10 degrees BTDC since June. This allows me to goose Tilly to WOT on all but the HOTTEST days without any pre-ignition pings. I retarded her down to just 5 degrees BTDC but that made for too much heat, and I eased her back up to this with pretty good results.

 

[John Kirby]

i tried to use a 68 chrysler system with 68 hp manfolds on 66. middle pipes were wrong

Had that pipe replaced years ago and it broke loose at the connection within two days. Was destroyed after dragging on the ground all the way back to the shop. Never saw a reason to have an extra connection there, no value added, just more expense and a future failure point. Have an exhaust shop use one pipe from the manifold to the muffler. My new yorker is dual exhaust though so it is trivial to make that pipe.

 

[CBODY67]

Checking ignition timing advance is one reason to have a "dial-back" timing light. Works very nicely!

If you check the OEM advance curve on the Fed-spec 383 2bbl, as in '66, you'll discover that the timing amount seems to be pretty much what the experts tend to like. With the '66-spec 2bbl, and the 12.5 degrees BTDC base timing, the total advance spec is right at 38 degrees BTDC total, but at like 4200 engine rpm rather than 3200rpm. This is totally exclusive of any vacuum advance amount at part-throttle.

When our '66CL42 was new, it didn't like regular gas, althjough it was spec'd for it, so we always used premium in it. No clatters of any kind. It would also easily tolerate 15 degrees BTDC base timing, too, no problems.

The problem with any replacement distributor is that it will have a "will work" advance curve, which allows the wide variation of engines they claim it will work in. BTAIM

Enjoy!
CBODY67

 

[Gerald Morris]

Checking ignition timing advance is one reason to have a "dial-back" timing light. Works very nicely!


When our '66CL42 was new, it didn't like regular gas, althjough it was spec'd for it, so we always used premium in it. No clatters of any kind. It would also easily tolerate 15 degrees BTDC base timing, too, no problems.

The problem with any replacement distributor is that it will have a "will work" advance curve, which allows the wide variation of engines they claim it will work in. BTAIM

Enjoy!
CBODY67

Sooo TRUE! I'm saving my nickels now to get a proper Mopar distributor, made 65-67 to replace the chineseum currently o it. I HAVE managed to time the engine to a happy point for the present at that 10 degrees BTDC setting, which I might nudge back to 12.5 IFF the winter weather permits it. Of course, 91 octane from Shell or Chevron still compares poorly to the RICH blue petrol of the Golden Iron Age, but with this stuff, Tilly runs very well. I pushed her up to 91 mph on the interstate last weekend with plenty give left in the throttle, just as one would expect of such an engine 55 yrs ago. No overheating or funny stuff occurred then either, so I think I've found the Golden Setting for this engine as its currently equipped.

Doubling the exhaust has modestly improved performance all around. I get 11 mpg in the city now. I hope to take her for a GOOD drive Turkey Day to see what highway mileage she now gets. "Blowing her out" on the road cleared some dirt from a lifter or 2 also, which I'd hoped for. All the dust, exhaust and crap from constant city driving has polluted the air filter badly, so today I'll attend to that and a couple others as I prepare for the more moderate temperatures of the "Not so Hot" season, which we pray will last until May next year if not June.

I need to start building that 400! I've driven Mathilda now for over FOUR YEARS, daily, in town. This itself attests to the superior quality and reliability of Mopar products from the Golden Iron Age. Be this as it may, it will be GOOD to have a freshly built replacement engine ready to drop in if this 383 gives any major trouble.

May your Moparian pleasures double mine!

 

[1966newport]

and pipe for a 68 still wont fit

 

[Gerald Morris]

and pipe for a 68 still wont fit

Nope! By 68 they'd changed a few too many dimensions. I stick with stuff from 65-67 for Mathilda, liking 65 if I can't get '66 vintage parts.

 

[Gerald Morris]

Have u did a timing curve on Tilly yet? That can sure help. Kim

Just did a total timing curve yesterday. I set the idle advance at 11 degrees BTDC at 550 rpm, w 17 inches vacuum. Runing this up without vac advance, at 3000 rpm, I had advanced the timing to ~34 degrees BTDC, all just off the distributor weights I reckon. Vacuum crept up to 18.5 inches, which is pretty consistent for this engine.

I then timed it with the vac advance attached, which gave me 39 degrees BTDC at 3000 rpm, starting from the same initial values. To wit: the vac advance pulls this distributor up about 5 degrees. I'll put my MightyVac on the advance tomorrow just to satisfy myself of this. I reckon a timing plate would be the best way to bump the advance down 5 degrees, which would leave that engine with 34 degrees overall advance, an acceptable value. I suspected the advance on this dizzy was a little high from pre-ignition pinging when I set the idle timing at the FSM specified 12.5 degrees. Getting some timing tape and a can of Rustoleum Clear Cote to securely stick it to the damper has been a VERY worthwhile investment.

 

[blue88]

Another fine tool to invest in.. is a fully adjustable advance timing light with RPM display. We use on the circle track cars to get your total advance at certain rpm.. 3000 is usually used. We don't use any vacuum and rely on full mechanical since we running at high rpm most of the time and adjust the dist weight springs and lock out the total with bushings on the weight pins.

 

[Gerald Morris]

Another fine tool to invest in.. is a fully adjustable advance timing light with RPM display. We use on the circle track cars to get your total advance at certain rpm.. 3000 is usually used. We don't use any vacuum and rely on full mechanical since we running at high rpm most of the time and adjust the dist weight springs and lock out the total with bushings on the weight pins.

I WAS aware that racers don't use vacuum advance, at least on flattracks, circle tracks and such. 'Twould be NICE to combine the tach w the timing light function to get total advance at given angular velocities. I plotted a few data points and did my arithmetic w my old fashioned Sears-Actron instruments. I like 40 yr old tools for a 50 yr old car and all. I like grabbing that stuff dirt cheap when I see it too! Copped some Snap-on brake spoons thus recently, which helps just now, as another thread of mine mentions.

Still, no doubt of it: an easier method and more precise tool for total advance would be a WELCOME addition to my growing home shop! Pity is; I now already need to invest in robotic surveillance and some gas blowback intruder repellent, in case some doped up little **** gets sticky protuberances around these parts....

 

[CBODY67]

AND . . . many hot rod tuners in the later '60s would block-out the vac advance, quicken the mechanical advance curve, and call it "better". Which dyno runs probably verified, but those dyno runs were at WOT, not part-throttle. So the mechanical-only advance was associated with "more power", which was what most owners desired. No real concern about fuel economy as many of them already had 4-series rear axle gears.

Some medium-duty gasoline-fueled trucks in that same general time had OEM distributors without vacuum advance, too. As they generally were operating under higher loads (aerodynamic and such), they were generally running at throttle levels which had lower manifold vacuum, so little need for vac advance as it would probably not be working (due to the lower vac levels) anyway. Road racers usually desired mechanical-only advance so that they had consistent throttle response out of the corners, and such, I suspect?

But when our '66 Newport 383 2bbl lost about 4 mpg on its normal average fuel economy, it was due to the failure of the vac advance unit on the distributor. Not efficient use of the fuel that went into the motor . . . and all of the side issues that might bring up, to me.

Enjoy!
CBODY67

 

[Gerald Morris]

AND . . . many hot rod tuners in the later '60s would block-out the vac advance, quicken the mechanical advance curve, and call it "better". Which dyno runs probably verified, but those dyno runs were at WOT, not part-throttle. So the mechanical-only advance was associated with "more power", which was what most owners desired. No real concern about fuel economy as many of them already had 4-series rear axle gears.

Some medium-duty gasoline-fueled trucks in that same general time had OEM distributors without vacuum advance, too. As they generally were operating under higher loads (aerodynamic and such), they were generally running at throttle levels which had lower manifold vacuum, so little need for vac advance as it would probably not be working (due to the lower vac levels) anyway. Road racers usually desired mechanical-only advance so that they had consistent throttle response out of the corners, and such, I suspect?

But when our '66 Newport 383 2bbl lost about 4 mpg on its normal average fuel economy, it was due to the failure of the vac advance unit on the distributor. Not efficient use of the fuel that went into the motor . . . and all of the side issues that might bring up, to me.

Enjoy!
CBODY67

As usual, your Wise Words advance my thinking wonderfully! Yes, I too have found a WORKING vacuum advance INDISPENSABLE to our 66 Newport 383, despite the paltry 5 degrees advance it gives. MOST of the advance on this sino-knockoff distributor comes from mechanical advance, which surprises me not in the least, as such is the rule to start with, and a feeble vacuum advance on this particular latter day, after market copy helps assure relatively successful widespread acceptance. It also helps protect engines from inept shade tree butchery. To wit, it works well enough to give fair market return for the investment.

I've no complaint myself, but want something a little more optimal for our car. The matter isn't that urgent, though maybe by years end it will be upgraded with a proper rebuilt model specific one.

 

[fury fan]

Can you post some more info about that exhaust kit you bought?
The ebay link is stale.
The fit looks *really* nice!

 

[Gerald Morris]

Here's an up2date link to sat1966's store. These folks sell exhaust systems, with tubing made in Canada, which is decent!

Great deals from Classic Car Exhaust Systems in Chrysler-New-Yorker-1966-1969- | eBay Stores

Browse around. I REALLY prefer Waldron's work, but suspect they're swamped. Best of luck to ye. I'm not an exhaust man, and want to tighten up my work on Mathilda weather permitting, but apparently, these folks make a pretty decent exhaust system.

 

[fury fan]

Looks like it's not mandrel-bent, but that's not essential to most of us.
They do seem to have gotten the tailpipe hooks correct.

I've done home-brewed Summit X-pipe kits on 3 cars now using various purchased tailpipes.
Everyone raves about TTI, but I *hate* the termination on their TPs.
I bought a set of Flowmaster B-body tailpipes and the downspout angle on them is 100% better (but they do not curve upward, they run straight backward into a downturn).
But these ebay TPs look to have the correct upturn before they dump down. (I heard that called 'the Mopar hook' but don't know if that's good parlance for it, or something 1 guy made up)

 

[Gerald Morris]

Looks like it's not mandrel-bent, but that's not essential to most of us.
They do seem to have gotten the tailpipe hooks correct.

I've done home-brewed Summit X-pipe kits on 3 cars now.
Everyone raves about TTI, but I *hate* the termination on their TPs.
I bought a set of Flowmaster B-body tailpipes and they downspout angle on them is 100% better.
But these ebay TPs look to have the correct upturn before they dump down. (I heard that called 'the Mopar hook' but don't know if that's good parlance for it, or something 1 guy made up)

Right-on! I've been told, though with no authority, that these Canucs use the old Mopar factory punch cards to bend their pipe. IDK enough about this subject to give any informed statement, but anecdotally, this stuff installed pretty easily, and I take all blame for the slop in that. For the COST, these folks sell a MOST effective product!

 

[fury fan]

@ Gerald Morris:
Can you post a few pics of the result?
Such as tailpipes as viewed from the rear, both standing up and crouched looking straight into the license plate.
And a side view showing how much the pipes hang down in the front floorpan area?



Photo for posterity of the ebay kit mentioned:

 

[Gerald Morris]

I'll see what the weather does tomorrow, then IFF conditions favor my crawling under Mathilda for the purpose of putting a couple pairs of new hangers on that pipe, I'll happily take pix and share them with folks here. There are a couple pics of my initial work on the second page, with one shot from rear but yes, more pictures are warranted now, 5 months after the initial job. I think the passenger side pipe runs low under the front floorpan, and this is one thing IU hope to correct soon. I suspect some of this comes of a sub-optimal job of me tightening to the manifold flange with 3/8" instead of 7/16"-24 bolts, which I've since acquired for this and sundry other needs about the body.

Stay tuned!