Then I would say definitely 3.55 if not 3.73 (perhaps 3.73 if you have a raised rev-limiter). The taller Gen III size rear tires effectively turn a 3.55 in a Gen II into 3.33 gearing, and 3.73 with the tall tires is effectively a 3.55 on a Gen II. I say don't be afraid of short gears unless you do a lot of drag racing and you calculate that that big power car of yours will run out of top end in 4th gear in the quarter mile.
I'm thinking there is some clutch slippage at play there. Before all the good gear calulators disappeared I calculated my 3.55 car with a 0.64:1 6th and Gen II height rear tires as theoretically capable of right at 200 mph at 6,200 rpm (not enough power to really get there) which I believe would put me at 160 at fuel cut-off in 5th.
