I had a 350 Chevy with cam, headers, and 4 bbl. in a 27 T roadster, only I was running a Turbo 350 automatic transmission and an 8" Ford rearend with 3.55:1 gears. The combination worked great, but I always thought I would have liked a bit more bottom end torque to the tires. If you are going to run an overdrive transmission, you can afford to go a little heavier on the rearend ratio, maybe 3:70 as techinspector 1 has indicated. I think that your top end and gas mileage would suffer too much if you ran 4.11:1 gears.