go to crbscca.com, and submit a request. I'm betting that car will need to make 222 at the wheels to be in the hunt.

Take 271 and multiply by the ITR factor (I'm drawing a blank, anyone?) and you'll get the weight. I don't think it's brakes warrant an adder in ITR.

I THINK the ITR factor is 10.9, and that yields 2950.

Gotta double check those numbers though.

Now, if you think that 271 at the crank, which converts to 222 at the wheels is not realistic of what that engine can make in IT trim, then supply documentation, or at least clues to follow up on in your request. Dyno sheets, known builders experiences, etc. Otherwise, it'll go in at 25%.

(I don't know my late 80s Carreras that well, but off the top of my head, I think that 271 crank number is a streeeetch. Do some homework if you agree.)

Also, if the car is already a race car, great, but check issues like seam welding and cage attachment points to ensure SCCA legality. If not yet built, run a spreadsheet first, Porsches are expensive builds , esp 911s.