I was wondering if anyone has a chart for how big a pipe you need for so much power and my question is i have a 383 strocker with about 425 hp and i was wondering what size of pipe im looking at and what size headers i should be looking at. Thanks

 

I would put 1 3/4" primary headers on that and either dual 3" or single 4" after the headers. 1 5/8" primaries probably wouldn't hurt it too much, just not my preference. If you're really looking for perfection the primaries should also be 34"-40" long to tune for the 5000-6000rpm range.

 

4 inch is to big. Go with a 3.5 inch. Its good to 503 HP. 4 inch is good to I think 673 HP. I would also go with a header with a primary of 1 3/4 and a collector with at least 2.5 inch.

 

All right thanks i think ill do the single because ive been looking through and you have to sacrafice alot of clearance to run true dual.