FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: bsprowl on June 24, 2025, 11:21:25 PM
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I was going to use a set of Zoom 4.71 gears that I’ve had for years. 28 splines on the pinion for the yoke. believe my set is the drag race gear set, not recommended for the street. Is the 28 spline OK for an 800 HP motor. I didn’t even know they made a 35 spline “Pro Gears” set.
When do you move from 24 to 35 splines on the pinion?
Thanks
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800hp? What's your combo?
I don't think you'll have any trouble with 28 splines.
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28 splines are the weakest of the axles. 28 splines are replaced with 31 splines in performance applications from Ford, and aftermarket goes to 35 or more splines for high performance applications. We broke 28 spline axles at 10.75 seconds with slicks, and went to 31 splines and had no more issues. 800 horsepower if you can hook it up would destroy a 28 spline differential or axles first time out. Joe-JDC
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28 splines are the weakest of the axles. 28 splines are replaced with 31 splines in performance applications from Ford, and aftermarket goes to 35 or more splines for high performance applications. We broke 28 spline axles at 10.75 seconds with slicks, and went to 31 splines and had no more issues. 800 horsepower if you can hook it up would destroy a 28 spline differential or axles first time out. Joe-JDC
He's talking about the pinion splines, not axle splines.
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482 BBM block 4.25x4.25, Blairs Edelbrock ProPort heads 12.1 compression ratio, Bullet 0.730 Lift solid roller cam, two 850 Holley double pumpers on a tunnel wedge intake, custom built over the frame rail headers.
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if its drag race only you can get pro gears in 28 or 35 spline.i have a strange iron center section with 4.30 pro gears and big pinion with spool for 35 spline axles.problem solved right there!new pro gears are $650-$900 .
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How heavy is the vehicle? I wrecked my 28 spline gears after a season in the truck with the 520. If your leaving on slicks with a race converter and transbrake or a good clutch then you’ll eventually wreck them, usually chipped or cracked pinion teeth show up first if you inspect them regularly. I didn’t twist the pinion off but the pinion teeth gave up first but they were also a used gear set with an unknown amount of abuse on them before I got them. Truck was 4200 lbs at that time.
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'70 Maverick Race only, weight about 2400 pounds (hopefully).
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Somebody recommended "Quick Performance" in Ames, IA for gears and axles.
I just recieved a center section "pumpkin" with a Strange nodular iron case, 35 spline Detroit Locker, aluminum pinion support support, and 1350 yoke. I supplied the 4.71 ring and pinion gear set and they assembled it. They also supplied the 35 spline axles I needed. Less than $2000 total.
They were easy to work with, had ansers for my questions, and did not hesitate to allow me to supply the ring and pinion.
Highly recommended.
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Quick performance is top notch!
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I'll add my accolades for Quick Performance as well. I'm lucky enough that they are within an hour's drive. We've done business with them on a number of occasions and have been more than happy with the service and results.
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'70 Maverick Race only, weight about 2400 pounds (hopefully).
Your car is light, but with 800 HP, you know you should not go with a 28 spline pinion shaft.
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Well my budget doesn't let me go biggera this time. I wouild like to but they wanted $1200 for a 4.71 ring and pinion set in 35 spline s no one is making them now and that was the price for their last one.
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Based on recent experiences with a much heavier car (3300lbs) with a bit more HP and 14.5 wide race tires, as long as the gear set you are using is a SAE 9310 (aka."Pro") composition you aren't likely to have any issues. The only negative to my combination is, occasionally, if I miss the clutch setup I'll "bend" the teeth on the gears but that is more a product of my weight than your very light vehicle. Good luck.