What size headers for SBC 383
 

Our engine is near complete, it is a SBC 383 and should make at least 550 hp. It is 12.5:1 compression, Victor jr intake, roller cam with 0.6 inch lift, 292 duration. Brodix Racerite heads.

I have an old set of 1 5/8" headers, what size do you think is best for this engine? Thanks for your help.

With that kind of HP I would think 1 7/8" primaries on full length header would be best.

I have a 460hp engine running 1 5/8" and plan to go to 1 7/8" this winter.

Absolutely 1 7/8" hookers with 3 1/2 collector. i'm putting 2" on my Sonoma 406" and i'm buying a 2 1/8" weld up kit with 4" cpllector when the 434 goes in my Malibu this winter. I'm now running 1 7/8" on the 377" motor that's in the Malibu.
The 406" motor has the same lift cam as you have with flat top pistons.

Zip.