The problem with the Pro-Comp/Speedmaster stuff--(at least in the SBC/SBF heads) that I've personally seen more than once--Is the guides seem to be made out of wax. Ok a hard wax. The guides are shot in a few hundred km's . The worst part is the OD of the guide is not a common or nominal size like .502" I think they are some dumb proprietary size like .544"-.545" like Brodix. So if they are shot you have to order some GOOD guides from Brodix at about $25-$30 a guide. Have they changed the guide material since? I do not know--maybe? Hopefully. J.Rob
