[Cliff R]

Ya, it's probably tit to tat with these high HP pump gas "street" engines.

Even so, WAY back when KRE released the aluminum "D" port heads I built one of the test engines for them. It was 10.5 to 1 compression and used the Crower 60919 cam.

It made 502hp/467tq on the dyno with peak HP around 5500-5600rpm's nearly as I can remember.

A few months earlier I built and dyno'd a near identical engine with Edelbrock round port heads. I'll add here that neither the KRE or Edelbrock heads were ported in any way, but I did have to mill quite a bit off the Edelbrock heads as they showed up with 92cc chambers instead of 87cc.

The 455 with Edebrock heads cranked out 505hp/551tq with peak HP at 5100rpm's. The intake ports as cast in the Edelbrock round port heads are notable larger than the KRE's. So with more port flow you'd think it would not only make more HP but it would be at higher RPM's.....hum?

The other main difference in those engine builds and head were the combustion chamber shapes. The Edelbrock using the large "bathtub" chamber variety and the KRE's using more of a "heart" shaped chamber. About all we got out of the testing was that more port flow and bigger chambers was good for a few more peak HP, but made less torque and average power than smaller runners with the heart shaped chambers.

Of course completely different builds that what is being described here but obviously combustion chamber shapes play a role in power production (torque) with these engines.....FWIW.....