I have a 1970 Roadrunner that was a 383 auto car with a 8 3/4 and stock gears..3.23. I put in a warmed 440 (around 500-550 hp), six-pack, with a 4-speed. I want to go thru the rear end and change the gears. Any suggestions as to what might be the best or pros and cons? (3.73's, 4.10's) I just use the car for cruising and rodding around on the weekends. I was kinda leaning on the 4.10's but am open for suggestions. Thanks in advance!

 

JJM, save your money and stay with the 3.23 gears. Sooner more than later you will break that 8 3/4 rear! When that happens, get a Dana60 with 4.10! Don't waste money on the 8 3/4 rear...it won't live long behind a 440 with a 4 speed tranny in a heavy car.

just my .02 worth
john

 

I agree John, but I have already broken it... I have a friend that offered to fix it with the spare parts of a 8 3/4 he has left over for free. But I was thinking about going to a 4.10 gear while its out cost of $200. Will eventually go to a Dana, they are getting kinda hard to find.

 

lots of dana's around. Just need to have one from a truck shortened and the ends & axles changed

 

jjm -

Assuming you'll be changing gears, kinda depends on what you plan on doing with the car. 4.10's are great for the track and racing stop light to stop light, but running over 3,000 on the highway can become problematic - rpm wise and gas wise.

3.73 might be a better all around compromise, but there's no free lunch any way you do it.

Archer

 

jjm, If you need any parts check with Dr.Diff :http://www.doctordiff.com/?page_id=41

john

 

X2

 

If your going to be having some 4 speed fun with a 4.10 you might want a driveshaft loop for safety.