Right now, I'm running Dynomax side pipes (see pic below) on my '55 Special with a 401 engine & Super T-10 4-speed. The side pipes were the suggestion of a "custom" exhaust system guy, who couldn't figure out how to run duals to the rear. I really don't care for the side exhaust and the noise, after an hour or so, gets annoying (OK, OK, I'm getting old!). I don't have a bender and really don't want to do this myself. Has anybody else run dual exhaust to the rear on a '55 and, if so, how did you route them, what size pipe did you use, and did you use headers - any pics?? Thanks for your help, -Bob
it's the frame... it's set up to only go down one side of the frame. To run a dual exhaust correctly you'll need to mimick the holes on the one side on the other. That's probably why the exhaust guy couldn't figure it out. I know the 57's came set up for dual exhaust and am iffy as to wether the 56's did, but I pretty sure the 55's didn't, it's a little bit of a pain and I wouldn't trust the job to just anyone. This is where a plasma cutter and lift come on really handy...
zman, thanks for the reply. Yes, you're correct. The '55 driver's side exhaust pipe passed under the oil pan and y'd into the passenger side pipe, which went back through openings in the frame, to the rear. Access on the driver's side, is restricted due to the master cylinder being under the floor boards. '56 was the first year that duals were offered by Buick. Anybody else??
New Ideas!!!! This is a long shot, but how about running the two into a collector similar to the old setup, but kinda like a header, larger pipe of course. Then run one 3" back and then split at the rear. . Kinda like a HUGE "X" pipe. Sounds funny but the result may still be the same. if Duals aren't critical, use a larger flowmaster and one outlet at the rear. I am unfamiliar about the undercarriage of a 55 but if what everyone else is saying is true, try something new and break ground for others who follow. Don't shoot me guys, just a little free thinking
NailheadinCA: I had considered that early on, but I didn't know if that would be too constrictive or not. Guess I'll have to look into that again. Thanks for your reply. -Bob
4th (and 3rd I think) F-body's run a y-pipe into a single pipe back to a single muffler with dual outlets, so it can't be that bad. How much hp are you making ? I'm guessing it's similar to most of the other nailheads around here (midly modified from stock). If so, then a single 3" or 3.5" should be more than adequate for you. I guess that brings up the issue of if there looks to be a limit on how bog a pipe you can run because of space. Is there room for a 3" pipe ?
dual exh. on '55 HI, I run dual exhaust on my 55 Special. originally I ran old Belond style headers and small (2 1/4") tubes to the rear. Now I have built full length headers with 3" collectors through 2 1/2" pipes. Both ways I had to run the pipes under the frame which as you know-reduces road clearance considerably. It is no big deal for me around here as long as I remember to slow down for speed bumps.ou: The idea of running a large diameter pipe will work well for performance but the sound may not be what you desire. Also, I am not sure if you would be able to fit a 3" pipe all the way back on you car, I would not recommend much smaller of a pipe as there may not be enough flow for the motor. I would definately try to find someone who could cut (trim) holes into the frame on the passenger side and run pipes to mimic the drivers side if possible.:TU: How ever looking at the picture of your car, I don't think running 2 1/2" tubes under your frame will reduce the ground clearance anymore than the side pipes you have now do, and no one will bust your chops about a Y-pipe dual system. (I DO know how well they work, I have a single large system on my 454" suburban to keep the noise down.):Smarty: Good luck, let me know if I can help.
Bob Cutting holes in the drivers side may work but I'd check the brake master cylinder clearance. Judd
Thanks for the replies, guys! All good points to consider. Running pipes under the car will defeat one of my purposes, which is to gain a little more road clearance. Our roads here in the northeast, whether due to the severe hot & freezing cycles and the subsequent ground heaving, or just due to the incompetence of the government, is terrible. Our road crews do a poor job of road maintenance - even the patches aren't smoothed out and they create additional bumps. Suffice it to say, our shouck absorbers get a real work out around here!! I'm beginning to think the idea of running the exhaust pipes into a 3" and the 3" through the stock frame openings and then splitting them off again, into a kind of "K" configuration, is my only way to get away from the side pipes and gain road clearance. I guess I'll have to spend some time under the old girl and see what kind of clearances I have to work with and then find a guy with a bender to install them to my ideas. Thanks very much for all of your inputs. It's like being able to hang out in the garage every night and shoot the bull about cars!! :beer -Bob
Just for fun I calculated the area of a 2", 2.25", 2.5" and 3" diameters. 2"= .0218 sq ft 2.25= .0276 2.5= .0341 3"= .0491 So 2 x 2" is .0436 sq ft, or = to a 2.82" tube. 2 x 2.25" is .0552 sq ft or = to a 3.18" tube Basically thinking a constant area would be good for lower restriction. This could get complicated since the exhaust exits the manifold at high temp, starts cooling, that would change the volume according to change in temp. Anyway, the 2 x 2.5 into 3" then split to 2 x 2.5 or 2.25 looks good on paper.(computer screen?) I should get another beer and think about this! T
SpecialWagon65: Thanks much for your input and your calculations are an important point to consider. I believe that a 3" pipe will go thru the existing opening, but I hope to have the time to get the beast up in the air this weekend and have a good look under it to see for sure. Thanks once again, to all of you for your help and thoughts on the subject. I'll post my findings as soon as I can get under the car. Thanks, -Bob
o No: You may be just the guy I've been looking for. Am planning to put a 65 401 w/Turbo 400 into a 55 Special 2 dr sedan. Aside from changing to an open drive and a different rear end.what problems am I looking at? Is it a bolt-in....nothing to butcher.....I hope. Let me know if you have any insight to this project. Thanks Jerry B ls4@lakeisabella.net
401 in to '55 Hi Jerry, I am not sure who you were referring to about being the guy you are looking for but perhaps I can help some. I did mine a while back and had to make a few fair size changes. First the motor mounts are different, not a big deal but you have to start some where. Then the exhaust has different shaped openings at the heads, the 264-322 is round, the 364-401-425 is rectangular, you'll need different manifolds or headers. I found a rear sump oil pan off a GS Skylark (?) to clear the front crossmember. You will need to make a different trans mount, and add a trans fluid cooler. You will need to find a way to 'locate' the rear such as ladder bars, parallel leafs, four bars etc... That is about all I can think of. It is not an outrageous amount of work but will require some fabrication for sure.
exaust I ran the ppipes on my truck into a 3'' head pipe, then into a muffler that I built with a 3" inlet and 3" outlet. then into a 3" tail pipe. Runs like duals.
I have the same set up on my wifes BB Suburban. I run this to cut down on noise especially on long trips with the kids. The flow is good and saves on the cost of tubing and muffler..
