Picking a Rear End

[SSGT Mustang]

Originally Posted by Rory McNeil

What tire diameter, clutch type and car weight? A few years ago, I swapped out the Stock Elminator 302 out of my 85 Mustang hatchback, with my 331 bracket SBF (485 HP at flywheel), retaining the Jerico 4 speed (3.19. 3.00, 1.32, 1.00) and McLeod Soft Lok clutch, car weighed 3050 lbs, running 9 x 29 1/2 M/T slicks and 4.88 gears in the 8.8, I would shift at 6800, and go thru the traps at 7200, at 128 MPH. I have never really raced much 1/8th mile, but my car would go 102-103 MPH in the 1/8th, so I would ASSume that you would want to gear it steeper than my car, unless you were running shorter tires. On my car at least, I found the 5.14 gears for a 8.8 to be much weaker than the 4.88s. I broke 2 5.14 gear sets with the Stocker engine, running mid-low 12s at 107 MPH, but the 4.88s looked fine after 2 years of running 2 seconds quicker and 60 footing .25 quicker than the Stocker combo.

Let me guess. You cracked the wide end of every pinion tooth on the 5.14s.

Cryo and rem polish helps a lot. Also, the pattern is key. The depth number marked on the pinion is almost worthless. Talk to Indy gear. He's a wealth of information and can get you the gears cryo's and rem'd for a very reasonable price.

With the smaller pinion, you need to watch the pattern not only on the ring but on the pinion itself. Try to get the pattern to favor the small end of the pinion rather than the wide end. It'll spread the load better over the thicker material rather than the thinnest part of the tooth.

I had 5.14s in a nine second car leaving on the transbrake and the gears held up. Give it a shot if you need more gear in your stocker.