flynhi

What's your opinion on optimum final drive ratio (first gear X diff) for my 383 with about 450 ftlbs torque and 255/55/17 rear wheel/tires?

American Boy

Something in the range of 10 to 11:1 final drive is great for the street and occasionnal drag race with street tire.

I ran 9.08 and 10.78:1 with a 400 sbc on a 3800 lbs camaro and the 10.78 was by far better.

Stephan

Glensgages

I have run both 11.3:1 (2.75 x 4.11) and 12.54:1 (2.75 x 4.56) in a 3800 lb 10.3:1 cr, hydraulic-cammed 355"/8" converter/28" x 10" Goodyear slicked '79 Z28;
the 4.11s aren't as 'harsh' on the launch, offering more consistent 60' times, and my ETs are with-in .03-.06 of each other, too.