I seriously doubt you'll fit, even with modifications. I am 6'3" (about even legs vs torso) and 210 lbs and had the opportunity to drive a carbed QV a few years ago. When seated in the car, I literally had to have my head bent completely over to one side touching my shoulder just to be in the car. Needless to say it was extremely uncomfortable, and while I did manage to get the car around the block, I didn't go further because I couldn't see any of the mirrors properly while contorted like that. I was completely crushed as the Countach was a boyhood fantasy that I realized wouldn't work.
Then I bought a Diablo and felt much better...