rear end ratio to make happy rpms at freeway speeds

[moparmat2000]

Hi y'all

I have some gearing questions for you. I have an A-833 overdrive transmission im putting in my cuda. Im also slowly collecting the parts to shorten and rebuild an 8.75 rear for this car. I would like to get a ring and pinion that would allow me to have fun with the car in the lower gears , but allow the engine to run around 2300 to 2500 rpm in top gear at 70 mph. I will b running a 15" wheel with low profile tires diameter to be determined at this time. I was thinking either 3.55, 3.73, or 3.90 gears. I only am asking this as i want to buy one set of gears, and have the diff set up one time.

Anybody here have any facts on this one,

Thanks
Matt

 

[OldmanRick]

.73 o/d x 3.55 = 2.59

26" tire dia. w/ 2.59 = 2340 rpm @ 70 mph

Also......3.09 1st gear x 3.55 rr gear gives a launch factor of 10.97.....I've found anything over 9.50 is plenty for the street.

 

[rlevs]

there is a formula for this sorry i don't know off the top of my head but look at Rieder racing or randy's ring and pinion or type in ring and pinion they will have the formula and even charts for the proper gear ratio

 

[67Dart273]

Dis be'a multeeepull thread

http://www.forabodiesonly.com/mopar/showthread.php?t=213268