I know this is situaction where it's already done, but I'll throw this in. Any of you looking to convert to 11 studs, don't waste your money, it's not needed. In SCCA's F-Production, 11 studs are not allowed, but many have comprssion ratios as high 15.5 to 1, if with the right head gasket and 9 studs can hold down that kind of compression and 1275s not having a history blowing head gaskets when things are prepped properly, why would you want to do it? Total waste of time and money in my opinion on a street car or a race car for that matter.