well i'm getting into header size early for a custom set of headers that just go all the way 8 pipe into custom muffler, into single exit and resonator.
Engine blueprint build: 4340 forged crank @ 4.00"
its a super street engine small block build of mine.
Dart SHP 400 block, final bore size @ 4.165" . this is .040" over bore of 4.125" std 400 this equals 435.9833" (436" c.i.)
Pro Maxx 225cc actual runner CNC and stage ported heads @ 67cc chambers. flow is @ 310+cfm custom fabricated extra high rise octo dual plane ports matched.
12:1 compression (11.89:01) and 8.72 to 1 Dynamic Compression Ratio with XFI292 hydraulic roller cam. 750cfm carburetor all prespectively.
hoping for 450 horsepower and 450 torque
also this engine is available for build.
thinking of an extra long tube 1.5" custom header build with gradually curving tubes and collected in a custom fabricated by me, oversized chambered muffler with single outlet anyone recommend header sizes etc. or anything else? thinking 1.5 or 1and 5eights or 1 and 7/8" or 2" etc. thinking 3" 3.5" or 4" exit? and what resonator or how could idesign one? i might just use the 1 5/8th " primary tubes instead.

 

I have a 1979 Z-28 RS Camaro Pro Touring car. It have a 377 cubic inch Supercharged small block Chevy with all the bells and whistles. It has a Weiand 142 mini blower on it and I have 15 LBS of Boost .I run a set of Doug Thorley "Big tube" full length headers 2 1/4 dual exhaust Flowmaster 3 Chamber.mufflers out of a set of stock z-28 exhuast tail pips.The fit is very nice ,But since the car is lowered it does scrap on the big speed bumps. I would check with them and Hooker as well.