455 won....

455 won....

#2

#3
10 bolt was factory 3.42 ratio $$ miles as it came from the J-yard but had new arrier bearing and a Cast Aluminum rear cover with supports .

60 its last 60 foot was a 1.60 but car could run in the lower 1.5 if I wanted to launch that hard. Its best was 1.57.

So should I re-gear it and try it again ??? maybe new gears would last ????
IF so what gear...3.73 was my first thought. The car ran 7.28@97 in the 1/8 at about 3900 lbs with 5 speed man trans (TKO)
28x10.5 MT et drags or 275/60/15 et drag radials... I think its safe on the radials because they spin if you launch it hard at all.

Mass destruction!! http://forums.performanceyears.com/g...s/icon_eek.gif

That is typical damage. The gear came out of mesh, probably from deflection.

The 10 bolt is a strong diff. I have seen them take much abuse. You could beef it up slightly with a TA type rear cover with the preload bolts that go against the caps. Set the backlash at the minimum tolerance as well. The factory posi unit might be the culprit. It is possible that it is flexing.

It had the TA type rear cover with preload bolts FWIW. Back lash was a measured .010 when it was put back togeather and ran very quite until the end ..RIP.. It had probably about 40 slick launches maybe 20-25 in the 1.6 range 2-3 in the upper 1.5's.

My greatest fear. Well second greatest. Better an old set of rear gears than a new set of tranny gears. I've always thought my ST-10 would go before the 10 bolt rear when I can 60 ft. well enough to hurt something. I guess the TKO is working well for you?

My ST-10 went before my 10 bolt 8.5 rear with 3.42. I installed a Tremec TKO. I hope my rear doesn't end up looking like this one! RIP

I got REALLY GOOD at swapping out 10 bolt A-Body rear ends in my GTO (many years ago)
until I finally got smart and put a 9" Ford Moser rear housing under the car.

I broke 12 bolt rears too.

Tom V.

was that a factory gear set? hp aftermarket ring and pinion set are better im sure..

Probably would have helped if you had the after market cap installed. That will reduce deflection.

I got the rear from the J-yard, I believe it's a factory original gear set. Is it worth rebuilding it and trying again with a aftermarket cap ? ???

I'd stick another gear in it. Not sure the aftermarket caps would help much in this situation. Try to set the new gear up so that the pinion meshes more towards the inside of the gear, that way under load it will mesh towards the center of the tooth, rather than the outside of the tooth (which is what ripped the teeth off of this one). If it does it again, you only blew $175 on new gears. Those gears were likely factory gears, which are probably more brittle than what the aftermarket "street" gears are today. If the posi needs work now, no sense in spending more money in this rear, get a 9"...but if it's still ok, just stick another gear in it.

My car has alot of low 1.50 60 fts on its 10 bolt with no cover.Precision Gears and an Eaton carrier. Switched carriers mainly for the easier rebuidability of the Eaton 4 spring in place of the S spring. Stock carrier was in need of new clutches.

A steel cap won't really help much if you have the TA cover. The .010 backlash should be tightened up a bit and put the pattern on the "toe" as Brian said. Precision gears are good, but hard to find. Try and spend some extra time to see if you can find them.

I've been running their "street" gears in a 12 bolt for years and 1.42 60/ft times and a 4 speed. I launch at 6000rpms and have never broken the gear set (knock on wood).

Looks like you may have got lucky man!!! I bet you will be fine with a new gear set.

3.42 - definitely lower it to 3.73 or even lower. You have an overdrive!

ok, So where to find these precision gears ? The posi was working fine but what about the metal from the broken gears... wash it out and blow it out with air and run it ????? what about the carrier bearings.... do I need to replace all this ??? it did this on the track and a limped it back in to the pits and back on the trailer that's all.
I'm gonna have to study up on the gear mesh topics I guess it will be my first rear rebuild..

3.73 would get me to about 5500 RPM in the traps at the 119 to 120 mph traps the car indicated it was wanting to run last week I don't want to use OD in a race and the cam is only a 236 hyd so its peak hp power is about 5400 rpm...so spinning to 6k is probably a waste of time.

OK- so 3.73!