Is 426ci 360 a small block?

Every calculation said the cross section would choke the engine around 6,200 rpm.

And Guess What?

Tried different tunes on different dyno runs starting at 3,000 rpm on each pull and the most it ever made at 3,000 rpm was 481 lb-ft. Best peak torque was 572 lb-ft @ 4,800 rpm. The best peak horsepower was 603 HP @ 6,300 rpm. I have at least a dozen pulls that it made 600-603 HP somewhere between 6,000-6,300 rpm and was still around 590-594 HP @ 6,600 rpm. It will pull 500+ lb-ft from 4,100-6,300 rpm.

I guess the iron heads aren't doing too bad.

Oh, somebody will ask........10.83:1 compression, 91 octane from the Stinker Station, 165 psi cranking compression at 5,000' elevation.