[ssanto]

I've got a 68 Camaro with a 350, Sportsman II heads and rumpety-rump cam. Motor runs good but the exhaust is just nagging and annoying.

My exhaust consists of:

• Hooker competition full-length headers
• Summit do-it-yourself pipes kit with H-pipe
• Dynomax super turbo mufflers

Firstly, there is an exhaust leak on the header flange. I've tried multiple types of gaskets and even taken the header off and sanded the flange with large flat sanding surface. But I still get tick, tick, tick... really only hear it when idling and cruising around at under 2500 RPM. Which happens to be a lot of what I do in the car.

And the second problem is that when I cruise at about 2200 RPM, I get a BRRRPPP sound kind of vibrating/resonating from the back. I can only think it is the muffler because it started when I swapped in the Dynomax. I had started with Summit Flowmaster knock-offs which were too loud. Then I switched to Summit turbos... I liked the sound but noticed they were leaking. So I switched to the Dynomax turbos but now I get this weird BBBRRRPPPP sound right at 2200 RPM. It like comes and goes as I pass through that RPM. But it ONLY does it when I am cruising. If I'm in neutral and rev the motor it doesn't do it. I checked and the mufflers aren't touching the frame anywhere.

I'm fixing to pull out the interior over the winter to do some improvements there so I figured I might as well tackle this problem.

Any suggestions? What should I look for in a better header?


Thanks,
Sal

 

[lmsport]

You could try Red RTV on the flange.

Mufflers are a trial and error process

 

[2old2fast]

Not sure it matters , but I've had great luck with copper gaskets w/ hi temp ultra copper silicone .

 

[seven up]

I guess I'd consider welding in flex couplings close to where the intermediate pipes bolt on to the header flanges. Your description sounds like something is flexing, maybe the motor, where the pipes are not absorbing the flex and the header flange gives up the seal. Or the muflers and pipes are wobbling around and the motor is steady, something has to give.
What I don't care for in flex couplings is their usual short lifespan.