New to this site, soon to be proud owner of a 1988 MC18, for track days and vintage club racing. It has been derestricted but I want to do any other readily available performance upgrades (not planning to open up the engine this year) and wondering which are specific to the different models. The tuning guide on this site indicates there is no benefit to installing a central plug head on the MC18. Why is that? Also, Tyga lists carbon reeds and HRC stuffers for the MC21 but not the MC18. Again, is there a reason these won't work on the MC18? How about the total loss ignition they list for the MC28?

Also, what is the experience with squish clearance on the stock engine? is it normally under 1 mm, and if not, is there a problem skimming the head to optimize squish clearance? I don't mind running race gas (although it would be nice to mix with pump gas to control cost).

Thanks for any input.