Your Headers Are A Waste Of Money?
 

Nice series of Dyno runs on a 474CI Pontiac with E- D port heads. Some interesting results.
https://www.youtube.com/watch?v=eTOR9afWCRY

Good video.

I found the "same" D-port manifolds, off a 70 GTO, for next to nothing. Using them on the gal's 428 1973 Firebird. No head porting will be done.

Similar to my thread in the street section. Only lost 4 hp from 1 3/4 headers to ram air manifolds and 3" head pipes.

Cliff notes for those of us that don't watch online videos?

I saw that. Good info for people not wanting hassle of headers. Good performance.
I ran ra3 manifolds on my 455 for years with 2.5 exhaust.

Believable, for some combos. I think Exhaust Reversion is tackled in the Collector implementation, and that is where implementation matters after the Dyno eval.

This video has tons of great info,thanks. Fuel pumps and pressure, reading plugs, spacers, manifolds vs headers. I wish they would have given headflow and some vague cam specs, though.

totally unbelievable! I've done header vs manifold tests on the dyno and in cars with opposite results. The HP peak seams about 50-100 high.