1-5/8" headers in a 393w stroker??

Helmantel said:

I think 1 3/4 would be the better choice.

Look at it this way: a 1 5/8" header on a 393 is like a 1 3/8" header on a 302. I think most would agree this would be way too small for a performance 302.

Click to expand...

rbohm said:

to a point i agree. but since he is building a street engine, the smaller header is better. i am going to build a 300hp 289 for my 66 mustang, and i am going to use a 1 1/2" tube tri-y header because i want the fat low end and midrange torque.

Click to expand...

Helmantel said:

Smaller tubes are indeed better for the street, but you need to take the engine size into account. It's a 393, which is 35% larger than a 289, hence the pipes cross section should be increased accordingly. Believe it or not, but making the cross section of a 1.5" tube 35% larger results in a 1.75" tube

A 393 is a big block (cube wise), so think in big block terms

Click to expand...