About four years ago I purchased an engine that included a pair of 1.8 heads that were not usable for my purposes (SCCA F Prod). The heads have 48mm intake and I think 39mm ex valves in them. There doesn't appear to be any porting, polishing, flycutting or machining done on them except for the larger valve size and for using dual springs.

My question is what are the uses for these heads? I've seen the 48mm valve heads offered as a machining service by FAT. Are these a common set up for drag racing? They came on a motor using old Venolia domed pistons but the valve head was too big to fit in the valve pocket and had damages the pistons where they touched. Are these heads used with flat tops? Anyone aware of any other set up that uses these type heads?