Well the FR2000 lumps (dry sumped) were the most powerful from my experience, the oil system was cocked about with in them, oil squirters blocked off etc
in terms of what was done to them i shall ask my chap when i speak to him to get the exact answer, i know his wife did the cam timing on them LOL!
Only small differences i ever noticed were the actually balancing/weights of internal items, cranks, rods, pistons etc were VERY close when compared to a road car. If i find my old note pad i have a comparison of a road car engine and a cup racer engine, we fitted an ex cup race engine into a road car years ago and whilst i was bored i took apart 1 of each engine and weighed/measured everything