Umm I'm not 100% sure if we can use other valves we can run other Valve springs thoo ill try find out :D , We run the bigport head at the moment but on new motor were trying the 3k head as the wa2 runs one and it pisses so now were tryingg it, we running next weekend at narrigon with a bigport head the compression ratio at 12:7 instead of 10:7 so also trying thatt