I found a set of RHS alumiun heads for sale used The guy only want $800 but i havent been able to cross reference any of the numbers on the heads. He says they have 2.02 valves but he didnt know the runner sizes. Plus I think they have had some work done to them. He says "they flow like crazy " but he can't produce any numbers or any info about them. Are RHs heads any good or will can I expect the results I'm looking for from these heads ?