We're converting a 64 1/2 Mustang 289 automatic to a 5.0 HO with a 5 speed trans and of course changing the rear end gear ratio. I'm looking at a 3:50 ratio for the rear end. Any suggestions? This will be a street legal conversation with good hole shots and a sensible street driving role (fast but not a street rod per se).

 

3:50 gears are a good compromise, decent acceleraton yet won't make your car fuel thirsty as bad as something like 4:10's

But if you want GREAT acceleration & don't drive highway speeds much.. get the 4:10's

 

i would go with the 3.50 because you dont want to spin the tires as much when you launch it

 

If the engine is stock. Mid to low 3 gearing.

 

If you're running the T-5 5-speed trans 3:73 gears is PERFECT for street/strip. Shaved a second off of my 1/4 mile time and still took highway trips all the time in my '90 5.0 LX Stang. Stock motor with tuning, free-flowing exhaust, and a few bolt-ons. Nothing radical, probably running around 280-300 horsepower. Loved em!

..By the way, I got your message about the parts I need, shoot me a PM with what you got. I need some of the items asap. Let me know, thanks, and where are you located?

BK

 

Just curious Bwkelley. What were your before and after times with the 3.73 gears.
Were you 2.7 or 3.08 stock.

I'm enquiring because I'm tired of my 3.73. Having a 3.27 set up screwed together.

 

Had 2:73's Stock, Ran a 14.2 best ET, After 3:73 and tightening up (reshimming) the stock posi I ran a 13.3 best ET. HUGE Difference and it hooked up better as launching was not as difficult. With the stock gears it either bogged or I had to dump the clutch resulting in tire spin. A happy medium was not easy to find.

 

I just bought a 65 that someone shoved a 1985 Roller 5.0 motor in. Unfortunately they forgot some very important things. Here's some things you want to be sure you do...

Flywheel and Harmonic Balancer need to be 50 oz externally balanced instead of 28, dipstick tube hole in block has to be plugged properly, need to use the proper timing cover for a mechanical fuel pump and/or drill out for front-mount dipstick tube, distributor gear MUST be steel or brass NOT cast-iron, smog-air injection ports need to be blocked off, if using standard rotation v-groove pulleys you need a standard rotation water pump, if reusing reverse-rotation water pump and serpentine pulleys you MUST use a reverse-rotation cooling fan.

Good luck with the conversion!

 

3.73 is great is street/ strip i have them and love them. i also put a ford traction lock in as well to match.