A little personal experience. My 53 GMC was originally set up with a 228 and S10 T5. I checked the Hollander and found that all S10's with T5's were equipped with 3.42 rear gears (but 14"tires, remember)..Anyway I set up my Camaro rear end with 3.42s and all was well. Since then I've installed a hot rodded 270 with a Camaro World Class T5 which has the .72 or .73 Overdrive. Still works well, but I think the 3'73 rear gears might get the fuel mileage up over 20 instead of 19.6. Im turning about l850RPM at 70 MPH (verified by GPS) I feel the engine would like it better if it was turning about 2000 at 70 MPH.
