After searching and searching I cant find a straight answer. The engine will be set up for road race k24 block, k20 crank, extended rod, oil squirters, and between 9:1 and 10:1 compression pistons, either flat or reverse dome, and I plan to run a Rotrex c30 or c38 centrifugal supercharger, cam specs will have to be figured later. The head will be ported out for full top end power, vtec and vtc delete, welded closed chamber head. So, I need to know more about which head has the best valve/port angle, and plenty of meat to grind away. From my understanding they are all very similar aside from their stock port jobs, no? I've been told an rbb cast is thicker though, but I can never tell through the mass amount of misinformation floating around Honda sites. Reason for the radical build was I was going to build the k20 in my RSX, but it's got 85k miles on it, been rebuilt twice, and had 3 cranks in it, total hornets nest, I'm not going to let that loose again. It runs good now, I should easily be able to step up to an Integra, either a cheaper jdm itr, or find a rust free ls/rs/gs/gsr and do the chassis work myself. Money isn't an issue when buying the engine/head, but I don't feel like dishing out $2k for a cnc head... maybe, unless more bang for my buck, has a full valvetrain, nonvtec... Which it appears that's what the 4 piston racing pro 163 is, I still have to weld the combustion chamber though. If I went that route I'd probably get seats, seals, and guides from them and get ferrea s2018 or s10099 valve springs, spring seat locators, and reatiners myself. Cnc is obviously better than my hand work, can somebody justify that price?