Aussie Pro Stock runs at 400ci or under. The P5 is getting too hard to get, so much so that the only Team running a Dodge is getting their own Head castings done locally. They receive quite alot of help from Rick Watters @ Eaton Enterprises. They have run 7 Teens @ 185+ mph in a Brick Avenger. I think from memory the minimum weight is 2400lbs for those things.

P5 is without a doubt the King of small block heads. I would say that P7's would be a close second with the W8's kind of the wedge heads. A properly prepped W8 will out perform damn near any Small Block Wedge Head. Making comparisons with W8 heads that were originally on a Craftsman Truck or some other roundy roundy racing doesn't do a W8 justice.
Just my anyway
AL....