I am starting this post to try and help clear up some confusion. There have been a few posts about various new big block heads and people seem to be confused on if they are all the same.
There are some new castings being sold by several builderst that are,members here, other castings by Procomp, and yet a different casting on EBay.
The heads the builders here have been working with I was told will be called " Sidewinder"heads.
Although they look similar to some popular heads, they have some well thought out upgrades in the castings
I was lucky enough to get a set of these castings to review and work with and thought I would share some results
I compared them to Edelbrock RPM out of the box heads and then used the same Edelbrock valves so the comparison would not be skewed by any trick valves changing flow.
First numbers are RPM heads untouched, second is a Sidewinder untouched.

Keith