Now this will be a bit hard for me as I don't have the "vocab" needed but...
A few things that were brought up at a workshop I go to were
issues with oil and water?? Something about oil in an RB30 naturally wanting to stay up around the head and come down really slowly... etc etc, and this causing issues with reliability for prolonged use on a track (ie, not 400m sprints).
They also mentioned that there is a way to rectify this, BUT for a track car they wouldn't recommend it. One of the mechanics at the place was actually in the process of building up an RB30 w/25 head. He said if all I want to do is do drag racing, then there's no problem, but he wouldn't use it on a hot day around a track.
Is this all utter crap?
(looking to gain knowledge here, not start fights)