3 or 3 1/2 small rim . well you do what you have to.i try not to run them to close to the fire wall did some 2 1/4 tubes were away from the wall guy said his feet did get warm but 2inch tube is not to hard to work with. s10 would not be much fun but not as much fun as a chevy II with a stock front end with a bbc 9.800 deck block . i still would run two tubes inside the frame and two out