wesmigletz

I went and got an estimate for a new exhaust system for my '59. The shop suggested using either 2 1/2" or 3" oval under the frame, to an "X" with 3" in and 2 1/2" out, 2 1/2" over the rear, reduced to 2 1/4" for the bumper exits. The 3" oval tubing is about 2 1/8" tall. I have traction bars that hang down about 2 3/4 - 3" below the frame, and they do not drag.

Another option I'm considering is 2 1/2 mandrel-bent pipe all the way back, with an "H" pipe. To do this, I'd need to open the frame holes up to accomodate the pipe through the frame, and prevent rattles.

My car currently has an unknown 1 5/8" 2 piece header, with a 3" collector. If I have room, I'll likely add a flowmaster 1 5/8" merge, collector extension, with a 2 3/4" outlet.

The engine will displace 377 CI with 9.7:1 compression, intake flow varies between 225 - 230CFM @ .500", the exhasut ports had a peak flow of 202cfm @ .500" lift. The cam is an Isky solid flat tappet with .530" I/E, 240* @ .050", and 278* adv. on a 110* LC. I'm considering ordering the cam on a 112* LC and with a "4 - 7" swap. The intake will be a ported and raised factory 2 X 4. Carbs will either be a pair of WCFBs or a pair of 500 CFM Edlebrocks; I don't have the carbs yet. Your input would be appreciated. TIA Wes

71zman

I just replaced the muffler on my 1960 C1 with 2.5" pipes to a Dyno-max muffler, out with 2.5" to the bumper and then a 1 7/8" chrome tip through the bumper. I had a crossover between the two pipes installed rear of the X-bar in the frame. I had the local muffler shop do the work (San Pedro muffler in CA, Owner Tim). Excellent job. He welded all new supports to the frame, no rattles. Did not need any cutting of the frame to get through the X-bar, the 2.5" pipes fit. The Dyno max mufflers fit (although tight). He recommended the Dyno-max over the Flowmaster because I did not want the car too loud (my wife wouldn't ride in it). The car runs quiet around town but really sounds great when both 4 barrrels open up.

good luck

wesmigletz

71zman, thanks for the reply. What kind of clearance do you have for the 2 1/2" pipes going through the frame? Did you have any issues getting the 2 1/2" pipes over the rear end? Did you reduce your pipes to 1 7/8", or did you weld the tips to the 2 1/2" pipe?

BTW, how do you like the Edelbrock carbs? Are you running the 500 CFM carb? I'm considering a set of Edelbrock carbs for my '59 due the difficulty in finding and the cost of the correct carbs. Thanks again, Wes

71zman

Wes, I ended up with about 1/2" clearance around the pipe to the frame. Tim, the muffler guy, welded a support with a rubber bushing right past the x-bar to avoid rattles. 2.5" pipes bent over the axle no problem. The oval mufflers had to be tilted just right to avoid them hitting anything, tight fit. Used chrome tip extentions out the bumper, looks great.

The Edelbrock dual-quad setup is a top quailty. I am running two 500cfm manual choke carbs. The progressive linkage is made of stainless and brass and has many adjustments to personalize the kick-in point of the front carb to your driving style. I find that 95% of the time I run only on the back carb and can squeak out 16 mpg. But ahh, the other 5% with 1000cfm flowing feels like a nitrous boost...just hold on.

Not many problems with them, just a couple of learning curve issues like: 1) with the idle systems running on both carbs all the time, you never need a choke so I just hard wired my open (from experience, if you don't wire them open, your idle spped varies) 2) I went with the original dual quad air cleaner and had to re-fabricate the bottom plate because the carb spacing is different - an Edelbrock air cleaner would have probably fit the low hood clearance but I liked the look of the original. 3) After a hard run, the idle sits higher for a little while - I have no idea why? residual gas in the manifold? sticky linkage?
But all in all, I am really happy with the set-up and recommend it highly. If you are near the South Bay sometimes, let me know and you can check it out. bret

DZAUTO

Years ago, I bought a complete stainless system from Zierden (no longer in business) for my 56. The front pipes are the ones for the 2 1/2in manifolds like used on a 62, the rest is 2in. It never flowed well enough for the SB400 that is in the car. I just couldn't bring my self to remove and discard an expensive stainless system. Well, a few months ago I finally succombed and had my muffler shop fabricate a COMPLETE 2 1/2in system (aluminized pipe) for my 56----------------MUCH BETTER NOW!!!!!! As mentioned, the 2 1/2in pipe WILL clear the holes in the X-member---------its tight! The guy at the muffler shop that I use is a genius when it comes to bending and fitting pipe. Since 2 1/2in will not go through the 56 exhaust bezzels, I had him fabricate tailpipes like those on a 61-62. I took a photo of the end of the tailpipe on a 62 so that he could bend it with the little reaward turn at the end of the pipe and then cut it off at the same angle as a 62. WORKS PERFECT!!! ALLLLLLLLLL of my pipes and mufflers (2 1/2in outlete/inlets) are clamped together with 2 1/2in stainless clamps and I fabricated some stainless sheet metal and then had it welded to stainless clamps to duplicate the factory Vette hangers/clamps that are originally attached at the X-member and the rear cross member.
This is an excellent system and after a few adjustments were made after driving a few times, there are no rattles (which really surprises me with the tight clearance through the X-member holes).
By the way, I went with the Turbo style mufflers simply because I think the better duplicate the original tone of a Vette exhaust.

So, my opinion, don't go under the frame. Find someone who is well experienced at fabricating 2 1/2in pipe and have him make a custom system.

wesmigletz

Bret, thanks for the feedback on the 2X4 Edelbrock set-up. Regarding not running a choke, are your carbs rich at idle? I was actually considering running one manual choke and one electric choke carb. If I go with Edelbrocks instead of WCFBs, I'll probably contact Edelbrock for their recomendation. The local Chevelle club attended a cruise-in at Edelbrock last Saturday, but I couldn't attend due to little league obligations. BTW, I work in Torrance, and would like to check your car out after work sometime. I drive my car to work a lot, it's been my daily for the past few weeks.

DZAuto, thanks again for the advice. Your set-up sounds similar to what I was thinking. If my last exhaust estimate is an indication of CA pricing, I may buy some pipe and mandrel bends and try to fab my own. I have an extra pairFlowmaster Chevelle tail pipes, I haven't been under the car yet, but they look like they could be made to clear the rear. Thanks again, Wes

Ironcross

Several years ago I installed a mandrel bend 2 1/2 stainless exhaust in front of the mufflers and 2 1/4 out and over the axle straight out the back on my 62 without any frame cutting. I retained the stock 2 1/2 ram horn manifolds as it held the generator correctly. I have never found any header company able to make a better bracket than the original stock GM to hold that heavy generator in place at high RPM`s.

K2

Tom;
Do you think your exhaust guy can duplicate the tailpipes without the car in front of him. I have 2 1/2" to the mufflers but haven't been able to find someone who was willing to tackle the 2 1/2" tailpipes. I would prefer to have mandrel bent tailpipes over having to fabricate them from bends.
Klaus

DZAUTO

Klaus,
I'd say that it is not likely that it could be done without having the car available to do the final tweaking of the pipe. The trick is getting the bends JUST RIGHT where the pipe must go between the frame and trunk floor pan. In fact, on my 56, the tail pipe had to be made in 2 pieces for each side and clamped together.

SebringBill

I bought a Zierden stainless exhaust system for my 57 some years ago with the off-road mufflers and 62 tailpipes. All I had to do was get 62 style rear hangers and I installed it myself. It's been working (and sounding) fine for well over 30k miles now...OK, it's standard 2"; just my $0.02

BTW, my 57 had orig GM part #d 62 tailpipes on it...the original owner glassed over the access holes on the body just after the rear end a loooong time ago - seems he took his mother for a ride when the car was new; she said "I don't like the way it sounds - fix it or get rid of it!"

He fixed it. That's why I have the original unrestored exhaust chrome still on the car, too.

K2

Thanks Tom, that's kind of what I suspected as it gets pretty cozy over the axle housings. I guess I'll just fabricate my own.

Hi Bill;
How do you like that 3:08 by now. I am just negotiating on a set of 3:08 gears for mine. Good upcoming winter project.

71zman

Wes,
Edelbrock tech line recommended no choke, that is why I went with 2 manuals. I have had no problem starting when cold. It does not seem to be running rich probably because I paid for a guy with a exhaust analyzer to set them up and I am sure he tweaked them down.

I work in El Segundo, Torrance is close. I will send a email and we can hook up.

bret

whall

I have 2.5 inch exhaust system on my 58 vette with a chevy 400, and still have exhaust coming out the bumper without any cutting. To get the exhaust out the bumper, you split the exhaust right after the axle. The small tube goes out the bumber, while the larger tube is angled downward right at the rear of the body frame hidden from the public. Everything sounds normal and noone would ever know, and there is no smell of exhaust in the driving compartment.

Also to prevent rattling wrap the exhaust with header wrap whereever it is close.

wesmigletz

Bret, I look forward to meeting you and checking out your car. That's interesting about the choke situation. I'll be sure to ask Edelbrock why. I'm currently not running a choke, but my car starts fine and warms-up fairly quick.

Whall, thanks for the reply, I hadn't considered header wrap, but I can see how it would help prevent rattles. Wes

INMYBLOOD

Wow some of you guys really push the envelope... Makes me jelous. I have a mildly built up 350 I have headers and I have a custom 2.25 inch system Could be 2.5 but Not sure been on awhile. Mine necks down to 2" OD to fit out the bumpers. Sounds quiet but can bark when steped on. Remember as the gas cools there is less need for the larger pipe. I could not get my self to change but considered 61-2 area for exhaust dump. With out extensive testing I have no idea if my system is adiquite for my engine. I have gone 13.0 @108 in the quater with street tires and through the exhaust. So for me this is pleanty. I'm loving life and usually drive a few tanks of gas out of the car every other week. I could not stand to have a loud car. Good luck.

SebringBill

Klaus,

15000+ miles later I'm still tickled. The 5-speed/3:08 works just like the old Muncie/3:70 except...wow! another gear to grab!

Other than changing the ring & pinion and new bearings/bushings - a rebuild kit - I never touched the actual posi unit.

I'm hoping to drive out to the SACC convention in Truckee/Hot August Nights in 2006. I still owe you some

wesmigletz

InMyBlood, 13.00 @ 108 is a pretty good 1/4 mile time. Do you mind if I ask about the rest of your combo... cam, heads, intake, gearing? I'm hoping to get some high 12 sec times out of my car in street trim, but it won't be easy. I'm hoping to make my exhaust as free flowing as possible, because, I may put ported, stock exhaust manifolds back on it at a later date.

The opening in the fiberglass is about 2 1/2", so I don't think it would be a problem to get a 2 1/4" pipe through there. However, the bumper opening is only about 2". I was looking at spintech's website and they have tips that go from 2 1/4" round to 2 1/4" oval (which is just under 2" tall), which would fit in the bumper's exhaust opening from the back side. So it seems that I could run a 2 1/2" mandrel bent system over the rear, then run a 2 1/2" - 2 1/4" reducer cone to a 2 1/4" oval tip. I also like the simplicity of running the 2 1/2" pipe over the rear as Tom suggested.

Sebring Bill, I'm planning a similar rear gear set-up to yours. I'm in the process of piecing together a stock-looking rear to replace the Ford that is currently under the car. The Corvette centersection I found has a 3.70 gear, but the guy is offering me a choice of 3.08 or 3.36 gears if I want them. Freeway traffic does 80mph out here when it opens up, so I'm leaning towards the 3.08 gear. I found a 2.88 geared Super T-10 locally, so I'll probably replace the stock T-10 with it. The 2.88 first gear, combined with a 3.08 rear would give me a steeper gear off the line than the current T-10 and a 3.70 rear.

K2

Sounds like that might be a good excuse to plan another road trip. Linda and I want to do Route 66 again. We'll stay in touch as I aim to collect on that beer offer. Who says C-1s are undriveable for long distances!

INMYBLOOD

Wes... Is your 377 a 400 with 350 stroke? It's just my guess you'll have no problem with 12's. I've had to work on my times some. I'm basically driving by feel. No tach. It's on my list this year. But for me when I started shifting it earlier my speed went up and I was running consistant 13.13-13.19's This is all with 2 second 60' times. The best time ever was the 13.05 @ 107.78 I've gotten as low as 1.89 60' times but can never put the two together. Drag radials and I'd hope to click off some high 12's. My 350 is a 3970014 block camaro I think 4 bolt factory forged crank, factory rods with ARP bolts, Hyper flattops +.040, 041 GM heads, EdL performer, Holly 650 DP, Comp 280 230@.050, .486 lift I think. Headers, muncie, 3.70's 235/60/15 BFG's and 18 years behind the same steering wheel. Many Many times I wished for a 383, but I'm enjoying my car to no end. I'm almost divorced and I have 50% custody of my boys. When I'm single I'm in the car. Really I'll burn a few tanks of gas out of it. I drove it no stop from when I droped my kids off one week to the next. Work, groceries, date...etc. There is a picture of my car at the track on my hompage.

wesmigletz

InMyBlood, sounds like you have your combo pretty well sorted-out. Those are pretty good times for such a mild combo. My 377 was made by boring my 283 out to 4.00", and fitted with a 3.75 stroke 4340 crank that was turned-down to fit the smaller mains.

I checked your site out. You have a good looking car and kids. I tried to access your guest book, but was unable to do so.