[quote=63ChevyII]Tire will be 25.63" tall.
3.55s at 65mph with 700R4 (.70) = 2118
3.55s @ 65mph with T5 (.68) = 2057
Does that sound about right guys?
THose revs sound right.
I used my MPG calculator and found not a big difference in gear for your combo although I guessed at some stuff about the engine build e.g. a 390 Holley and 8.0cr.
I do calculate 20mpg or 19.9mpg for chopped 40 as he quotes and assuming he has a fairly stock 292, and for your car at 65mph cruise I calculate:
5spd
18.78mpg 3.55 gear
19.10mpg 3.08 gear
700r4
17.00mpg 3.55 gear
17.51mpg 3.08 gear
Some cars are very sensitive to gear but in this range yours would not appear to be. With 3.08 the revs would be really low. What I would do is leave the 3.08 in there and see how you like it. Unless it is a posi you will likely have traction problems either way and have to swap the rear, that might be the time to go to 3.55's, and a posi if the 3.08 is lugging more than you like.
17.51
