i am going to have my machanic remove my stock 73 manifold with the smog pipe thing on it and replace it with a new jet coat header from msa, or a used stock manifold from a non-smog 240. i'm having him do it because the old manifold is leaking and one stud is broke off. my problem is i can't decide on what is better the headers or the manifold!!! can you please tell me the pros and cons of both. the things i want out of it is performance, longevity out of my motor, longest life, efficency. i dont want somthing that will warp or kill the engine over time.
i also was thinking of getting msa twice pipes, but im not sure of them either. what do you recommend?

thank you

 

I would NOT do 6 into 2 into 1 like my 72. Do what I had on my 73: 6 into 1 header (MSA) with 2.5" exhaust. lots of torque. cheaper, simple. the 73 had 157 rwhp with medium cam.

 

except make lots of noise. the stock exhaust manifold was designed so well the adding headers wouldnt give any extra performance. its actually a waste of time and a waste of money. now twice pipes DO give you a performance gain, but headers wont. spend your money on a good exhaust system from the bottom of the exhaust manifold back. also grab yourself a cat to match the size of the pipe you are going to use. get a large diameter pipe. the larger the pipe, the deeper the sound. i had 2 1/4 put on and it sounded like a bumble bee. i didnt like it, so i had 2 1/2 put on. kinda sounds like a growling beast now. I recommend:

*stock exhaust manifold
*bolted flange 2 1/2 pipe from manifold to 2 1/2 inch catalytic converter
*bolted flange on both side of the cat to ease removal
*2 1/2 inch pipe from rear of cat to muffler
*3 inch inlet/outlet muffler

I promise you if you go with this setup you will be happy. i have TONS of experience with exhaust. I have changed mine over 8 times and have spent over $1000 on it. I did it all in finding the best setup , so trust me lol. Good luck dude

SoCalZ Prez
http://www.socalz.org