Since the sixties several 4wd sports car with brainpopping power have been used in heavily sponsored race cars from Indy, f1 to Le mans however the best, most reliable and fastest have been and still are RWD in lightweight cars.
The datsun is lightweight and with its small wheelbase and track should remain that way for racing. Le mans is the equivalent of the hardtop f1 cars. If a 1200 should be 4wd then it should be as light as a 1200 rwd with the same engine spec to be able to compete with it or say its better.
As a pure exersice in difference... yes it will be different but a late lightweight fwd 4 cylinder turbo engine midmounted behind the back seats of 1200 would be simpler (well if you have the resources to go 4wd in the first place) and with the same hp would eat it like a snack. Otherwise a lightweight gaerte 340hp NA chev based 4 cyinder with a late cadillac fwd gearbox all mounted behind the back seats would be lighter and easier to work on (OHV see pic on gaerte in photo section) and has big hp off the shelf everything from chev even a big variable nissan turbo on it would take it further ahead of the evo engine and would be a little nissan touch of breathing to an otherwise non nissan heart.