I was wondering if you people know if I can get away with a 1 5/8" primary header tube with a 450 flywheel horse 383 TPI?

 

Yeah, you can use them, but you're way better off with 1 3/4".

 

I'm using 1 5/8 full length hedmans on my 383. I think 1 3/4 would be a little better but I didn't want to go through the extra hassle of making the 1 3/4 hookers fit...I bought them and they didn't fit my car well at all. I saw a recent magazine article where they built a 383 it lost about 10-12hp on the top end with 1 5/8 vs 1 3/4.

 

Your going to have to pay for the SLP 1 3/4" headers. They fit noce and to my knowledge, they are the only 1 3/4" shorties for third gens.

 

If you can, go with the 3/4". I think hooker's lt (2055) headers are 3/4", of course those are lt's though, but I wouldn't reccomend shortys on a 383 unless you have to.

 

I've got 1 5/8 on mine.. shorties to custom made Y-pipe to flowmaster collector, to NO cat, to dynomax muffler, WORKS GREAT!