They have 2.08 intake, 1.65 exhaust. They are supposed to be ' race ported ', whatever that means. This is the engine that was in the car when I bought it in 2019. I haven't done anything to it other that pull the heads this past winter to make sure I didn't have any damage due to a pushrod failure at the last race of last season. Luckily, there wasn't any, so I cleaned the heads and the pistons and reassembled with new head gaskets.