just wondering what is the max hp output you can put on a stock rebuilt 10 bolt with 3.73 new bearings the works. and if anyone is running in the low 12's with stock rear end set up with gears thanks thomas

 

Whatever the top engine in 1986 made for horsepower is your answer That is around the time Ford went to an 8.8 rear because they were making too much power for the 7.5 Also the 3.73s make it somewhat weaker than factory 2.73/3.23/3.42 just because the teeth are physically smaller. That said, I usually used to blow out the posi's before I break the gears, but on the bottle from a roll I managed to mess up some gears a bit too

It will depend on a few things...How luck you are, whether its behind a 6 speed or auto, how sticky of a tire you are running and what sort of launches you do.

There are guys here that have run 11s or deeper, myself included, on a 10 bolt. But if you are driving it 'right', it shouldnt last too long. The ones that live are the exception to the rule, so just be ready if you plan on kicking its a$$.

 

thanks i appreciate it i guess i will look into a new rear end what would you suggest 12 bolt or 9inch and what is better for the money slight budget thanks thomas

 

if you are planning on usuing the stock rear for a while- there are many things you can do to get it to last a little longer- but the three main things i would do is: get a good set of gears, a girdle with the preload bolts/studs, and weld the axle tubes. what normally kills the 10 bolt first is case twist/deflection since it's so small- the girdle and welded axle tubes help strengthen it a little bit.

as far as your question about 12 bolt or 9"- i would say that a 9" is better and takes less power to turn that a 12 bolt. however a 12 bolt is a stong rear and is a cheaper to build than a 9"

 

You have your 9" and 12-bolts mixed up. 9" eats more power, but is usually slightly cheaper than a 12-bolt.

 

you may be right about eating power- but i thought the 9" cost a lot more to build- i guess i could be wrong- crazier things have happened

 

I believe a 9" is cheaper but you should also consider, for example, that a Strange 12 bolt is a direct bolt in replacement for the factory unit. This makes for an easier replacement but you pay $ for it.
Also, if you were to keep using the 10 bolt, there seems to be alot of used replacement ones for sale rather inexpensively. Mine held up for over 20,000 miles with over 400RWHP and an M6 but I never severely stressed it with hard launches. The aluminum cover with bearing supports is a must for any 10 bolt, in my opinion.

 

If your running an auto the 10-bolt should last for a good while in the 12's. Time in sig is with a 3.42 geared 10-bolt and built 4L60E. My previous gear set lasted over 3 1/2 years before a few teeth broke. 60's in the 1.5's-1.6's.

 

You are talking about welding the "axle tubes". Where are these located at?

 

I welded mine last week (have 11 sec car). You have to weld where the go to the pumpkin so they wont move/spin when you accelerate...
Sebastian

 

i've heard 400hp w/ a automatic trans from a couple local guys. im currently pushing mine at about 340hp from a 2000-odd stall with full 10" wide slicks. holding up fine. i think some people are to abusive and others get incompetent builders to install their gears.

 

that always plays a major role the person installing the part

 

Put axles and a pre-load cover on my 7 1/2. Also richmond gears. 3.73. Finally broke the pinion. The torsen heavy diff held up. Now going to a 12 bolt.

 

when you weld the tubes do you have to worry about warpage or drain the gear oil or anything like that?