I need a new exhaust system for my completely stock engine. It has factory log manifolds although I might consider R.A.R.E. replacements.

My old system had glasspacks with no crossover, 2" up front, 2" or 2.25" in rear. That sounded fine (no resonance) but didn't have good scavenging per Jim Hand's book.

1) Is a 2.5" system (with H or X crossover) oversized for the 326? Same question for R.A.R.E. long branch manifolds. I need to keep the low end with a 2 speed automatic.

2) I don't have a welder - is it reasonable to clamp the whole system as long as I use sealant? I don't want to tow the car to a muffler shop, but might get it welded later after it's drivable.

Joe, I would think a 2.5" system with a cross over would be just right, since the 141 heads are a little better than the 140's and you should gain some with a better breathing exhaust system.

http://www.pypesexhaust.com/ is said to have a great bolt on/weld up system with an X cross over etc... I've heard many say it went on just as it should, and fit with little or no tweaking.

Gardner and others make a good direct replacement system too...

You should be able to clamp the whole system, and then have it welded later.

Brett - 67 Drop Top 455!

Brett - I've looked at the Pypes, Flowmaster, Parts Place, Magnaflow, etc. The Pypes web page claims their downpipes don't fit the stock manifold and they haven't yet responded to my e-mail asking for a solution. That's probably the system I'd end up with if they have an answer, though.

Has anyone with a 326 or 350 changed from a 2.25 to 2.5? What happened to the 'seat of the pants' response?

Joe, maybe give Bob Everett at Evergreen Muscle Car a call: (253) 735-2402 - Auburn
http://www.evergreenmusclecar.com/index.html

Tell him Brett sent you to find an exhaust system that will work for your H.O.

He should have some ideas on the best way to go, or the best place locally to get it done. That's what I would do... We gotta get you going soon! Only a few months till... we Might start thinking... about cruising!

Brett!

The factory 69 400 RA III exhaust is 2 1/4". I've got 2 1/4" pipes with long branch manifolds, two resonators and a transverse muffler which is pretty much the RA III exhaust and it seems like it breaths plenty well for my 389. Unless you're really hardcore about making some serious horsepower, 2" or 2 1/4" pipes are plenty. But that's only one man's opinion.

A buddy of mine tried to tackle the exhaust himself, but gave up after a while. Drove it to the exhaust shop some 25 miles away (mostly back roads) with open headers. Uh - let's just say it was a bit loud when he got on the gas! He was setting off car alarms as he passed! Hahaha!

Luckily no police pulled him over. I'm actually trying to think what the ticket would be - probably the same as the "ricers" get with loud exhaust systems. Usually it's a "fix it" ticket where they have to replace their loud muffler and bring proof to court. Luckily for you, you'd be on your way to the exhaust shop anyways, so you might be able to have some fun!

Of course, I'm no lawyer, so I can't exactly say what would happen - plus, with no back pressure, I'm sure you'd be backfiring underneath the car every time you let off the gas. Can't be too safe.

your best bet is to take it to a muffler shop.just make shur the mechanic knows how to bend pipe.a good muffler man should be able to make a duel system and make the left exactly match the right side but in reverse.

Make sure the muffler shop , or whoever is doing the work has done 1st gen firebirds or camaros. They need to be next to perfect , as it is a tight fit. I had a bad experience with a national brand muffler shop.

Naw, it wasn't me. I managed to cobble something together.

Oh, yes go with a 2.5". I stand corrected about the 2" exaust, and I'm man enough to admit when I am wrong. (I have been wrong before. Back in 62: I thought I was wrong, but I was right:)

Anyway, my 2" exaust had rotted off at the back of the mufflers. I installed 2" tailpipes, and it restricted the engine quite a bit, compared to the exaust ending at the end of the mufflers. If I go with a new exaust, I'll definatly go with a 2.5".

Just to wrap up the topic:

I bought and installed the IMCO original-style system that Snow Cruiser mentioned in another thread. It went in without too much trouble, although I STRONGLY recommend having at least two people helping.

As delivered, the over-axle pipes were hard up against the rear axle and almost impossible to install. I had to trim the downpipes, resonator inlet and outlet, and over-axle pipe inlet several times to get clearance there and also between the crossflow muffler and gas tank.

When the car's drivable I'll probably take it to a muffler shop to get the fit better and weld a couple of joints. Haven't fired it up yet but will post again with sound impressions.

Did it work out well?
Any pics?

2.5" is fine as long as you have restrictive mufflers.

I suggest welding exhaust systems.

The exhaust was much quieter than I expected and prefer, although I'm still having trouble keeping the engine running and it's probably running way lean right now. After I get that ironed out I'll know more about the sound it's making. It hasn't been running long enough to see how my clamp job works, but I'll likely get it welded. Not a fan of carbon monoxide.

My Brand-X car with 4.6 liter has cat-back Flowmasters and sounds how I expect an American V8 to sound. I may replace the rear crossover muffler in my Bird with the Flowmaster loud one. Or just dump after the resonators.

By the way, Snow Cruiser posted some pics in his original response on the topic here:

/forums/ubb...CO&topic=0&Search=true#Post37841

Don't know if that link will work or not. If not, just search for IMCO and look for a post by Snow Cruiser.

I went with gardner exhaust. the cost was 1500.00. they built to specs with an exact fit. it was 2.5 inch stainless comes with everything. I installed it with no trouble right up to my factory headders. took 6 wks to receive. you get great customer service.

68 400 h.o 4 spd to go!!