Exhaust System Kits and other questions

[scgamecock]

Does anyone sale a complete exhaust system kit with headers?

How big of pipes can I run from headers back?  I would like to get as large as possible without running into clearance issues.

What is the best size and brand headers for a 351 CJ?

What muffler gives the best performance and sound?  Looking for something really deep that will enhance the sound of a cam.

 

[Hemikiller]

IMO, "best" is all opinion. So....

Best fitting long tube header - Hooker Competition 6915

Best size tube for a 351: 2 1/2"

My two favorite mufflers are Dynomax Super Turbos if you want a mellow sound with minimal resonance. Hooker Aerochambers are a little louder, but still not bad on resonance. No matter what, you need to run an H or X pipe.

If your car is an an original Q-code, it has staggered shocks. Tailpipes for this can be a challenge.

 

[73pony]

check with Don at OMS. He has a supplier that makes kits for our cars and they are an excellent fit. I know several people on this forum have the kits from him, myself included. Mine came set up for stock manifolds, which I was running at the time but switched out to headman headers and had to obviously modify the exhaust to work with the headers. I am running the "run of the mill" turbo mufflers. They are "OK" will look at upgrading them in the future.

 

[red351]

I ran the stock 2 1/4" style system for a good number of years, and felt the crush bends was not doing well performance wise. I once had a spark plug blowout and some of the porcelain went down inside. Well I guess (the only way it could) is a piece went by the intake heated cross over into the a cylinder on the engines opposite bank leaving some impressions on that piston top also. Must be some bad things going on inside the cast 4V ex manifolds at 5K plus RPM's. Got the Flowmaster 2 1/2 prebent pipes (not their mufflers) and they did not fit well. Ended up using what I could cutting and welding making my own and going with Sanderson shorty headers.

 

[Jeff73Mach1]

If your car is an an original Q-code, it has staggered shocks. Tailpipes for this can be a challenge.

Very true! I converted my car from staggered shocks to standard shocks to fit my 3" system and since I run Caltrac traction bars the staggered benefits were pretty much eliminated anyway.

 

[Carolina_Mountain_Mustangs]

I just took a system off parts car I bought that was two weeks old when the car got crashed. They fit pretty good and were made by Pypes. It also had ceramic coated headers would have to check number does not have a name on them. They fit great also and did not hang down like some do. The sound was good also but the engine was just stock. You can go too big with pipes and hurt the performance. The formula for calculating header length is the same as used for calculating the pipes for a pipe organ. The rpm range and frequency of the valves is what determines the best length and size. No one header is perfect for every rpm range that is an impossible situation. The pulse of exhaust should exit the end of the tube just before the next comes and actually pulls the exhaust out if right length at the rpm you run the most. My old boss man in race shop use to make his own headers based on the rpm range he was running on a certain track. Google it. When we kart raced the same thing you ran a certain length pipe for the rpm you ran at and could be different for different tracks.

This was on a 72 vert 351 C with 3 speed. I am going to install on my CJ 72 Q code when I build it. The only thing I did not like was he had to put a piece of box tubing between the plate that goes under the drive shaft on the convertible to clear the pipes. I did manage to take the system off in one piece since it was welded together. Will have to put in with rear out of the other car the crashed one was bent enough to clear. It was clamped and welded.

David

 

[red351]

That looks close to what I made except the u clamps and blended the welds better.