Recommended Rear End Ratio...

[sdkar]

Okay, I am up in the air on a decision and looking for a consensus of what you guys think.  I have a 69 Camaro that is going to get a 502 Crate Motor, A Tremec tko 600 5 speed manual transmission and a Ford 9" Rear.  I am going with the Martz Rally and Road Race front subframe and a TCI 4 link setup in the back.  I have been given a choice of a rear end ratio.  Well, I have no clue at all what to tell them.  This car is going to be a daily driver and not raced.  I want something that leaves the line quickly bt will cruise nicely at 80-90mph down the highway.  I have been told anywhere from a 3:40 rear up to a 4:11.  I don't want too radical, but I don't want a dog either.  I am going to go with the majority of what you guys say.  So, you all get to help me build my car.  Tell me what you think and if so, why. 

Thanks for the help.

Steve
sdkar@bellsouth.net

[gro51]

Daily driver you say?  3:73 would be a safe bet.

[McKenzieDave]

Which overdrive ratio did you order (.82 or .64)?  Which 502 is it?  Dave

[sdkar]

502 Chevrolet Crate motor 502hp and 567 ft. lbs. torque.    The transmission ratios are as follows:  3.27:1, 1.98:1, 1.34:1, 1:1, and 0.68:1.

[hotrod68]

I'd think with a 502 it would hardly matter . A little small-block needs deep gears to get the revs up, and that 502 is a torque pig! I ran mid-12s with a 400, Turbo 350 and 3:55 gears in a '68. I'd go with 3:55s 

[My68SS]

3.55 is my vote, and even at that you will need a delicate right foot in 1st gear with that amount of torque, even on a dry road!
I certainly think that at anything greater than 3.73, 1st gear would become redundant

Some other guides are:
On an overall tyre diameter of 24", a 3.55 diff will give about 20mph per 1000 rpm in 4th [1:1]  and your first gear will give about 30mph @ 5000 rpm.

[JohnZ]

I'd go with the 3.55 also - you'll have all the tire smoke you can handle in 1st and 2nd, and the equivalent of a 2.41 axle on the highway in 5th.