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Organized Drag Racing and AutocrossDrag racing and autocross discussions and questions. Techniques, tips, suggestions, and "what will I run?" questions.
What can be done to strength the 10 bolt for racing? I am a low horsepower car foot braking on slicks, so I don't think it will take much abuse. However, I would like to try and strength it this winter for next season. I already have a mini spool at the moment, since I had an open diff. But, I plan on buying a main cap bracing cover and either Richmond or motive gears. Other than those things, what else could I do? Also, I realize that this won't last forever. A 9" will be in its future, but just something somewhat cheap for now. I don't have $1600 right now to dump into a rear end of a car I just race
I honestly wouldn't touch it and save that money. You shouldn't hurt it with low horsepower and footbraking. I went 10.6 @ 136 in the 1/4 in my 4th gen off the footbrake with the stock 10 bolt. I beat the crap out of it and it was still good when I ditched it for a 9".
What can be done to strength the 10 bolt for racing? I am a low horsepower car foot braking on slicks, so I don't think it will take much abuse. However, I would like to try and strength it this winter for next season. I already have a mini spool at the moment, since I had an open diff. But, I plan on buying a main cap bracing cover and either Richmond or motive gears. Other than those things, what else could I do? Also, I realize that this won't last forever. A 9" will be in its future, but just something somewhat cheap for now. I don't have $1600 right now to dump into a rear end of a car I just race
Since nobody wants to actually answer your question, here’s what I would recommend for beefing it up.
Aftermarket cover with the cap brace studs, as you are planning to purchase.
Weld the axle tubes all the way around where they go into the center section.
Stronger gears
28 spline axles, (I think that’s the spline count of the later year 10 bolts) older ones were 26 if I recall.
Fresh fluid won’t hurt anything either.
Have the backlash set as tight as possible. The gears will whine, but it will help. Also, no “dry hops” after the burnout. It’s a waste and will hurt the gears. Finally, stage with the pinion teeth against the gear teeth to lessen the shock.
You can easily spend over $500 upgrading with new axles, posi, rear cover etc, etc but it will still have tiny ring and pinion teeth which are what will fail first. Even spending $1000 in upgrades is not worth it.
Run what you have for now and save the money you wanted to invest in a tiny 10 bolt for a 9", 12 bolt etc. You don't need to pay for a diff twice and if you break the 10 bolt before putting in a 9" then the incentive for a better diff becomes a priority or you can spend a few hundred bucks on a junkyard replacement to keep you going.
I ran a 3.27 geared 9 bolt into the very high 11's. Gearing was all wrong and it was cheaper to build a beefed up 10 bolt that had better aftermarket support. Pushed the 10 bolt into the low to mid 10's before finally putting a 9" under the car and never looked back. Just wish I never wasted all the money building up the 10 bolt.
Since nobody wants to actually answer your question, here’s what I would recommend for beefing it up.
Aftermarket cover with the cap brace studs, as you are planning to purchase.
Weld the axle tubes all the way around where they go into the center section.
Stronger gears
28 spline axles, (I think that’s the spline count of the later year 10 bolts) older ones were 26 if I recall.
Fresh fluid won’t hurt anything either.
Stronger gears as in? Motive, Richmond, etc? I plan o them being 4:10s
spend the money on an extra 4th gen rearend and keep running as you are now while saving money. as stated above, you can go low 10's with a stock 10 bolt for awhile if you dont shock it too hard. (clutch dumps, etc.)
the overall problem with it is the design. the parts inside are only so big.
If it's just a drag car then don't spend the money trying to beef up the 10 bolt. If you can find a cheap set of 4.10's to swap in it then do it, but I wouldn't touch anything else. Like stated above, you can get by for awhile on the 10 bolt being an auto leaving off the footbrake. You shouldn't shock it hard enough to break anything for awhile.
Originally Posted by NoEmissions84TA
Changing to 4.10s makes the problem of the small and weak gears even worse. The pinion gets physically much smaller with this ratio.
??? The number of teeth on ring gear & pinion change The physical size of the ring and pinion do not change...
IMHO if you plan to upgrade to a 9" all those upgrades on the 10-bolt is money saved for the 9"
If you add up all the mods and the cost for a shop to do them to the 10 bolt.. you could just buy the 9" for the same amount.
spend the money on an extra 4th gen rearend and keep running as you are now while saving money. as stated above, you can go low 10's with a stock 10 bolt for awhile if you dont shock it too hard. (clutch dumps, etc.)
the overall problem with it is the design. the parts inside are only so big.
That's the best way to handle the situation. If you aren't making big power at the rear wheels (>500) a Ford 8.8 could work nice and possibly be less expensive. If you are interested in a cover girdle I have one I am selling for $100 shipped. https://www.thirdgen.org/forums/engi...t-support.html
Originally Posted by NoEmissions84TA
Changing to 4.10s makes the problem of the small and weak gears even worse. The pinion gets physically much smaller with this ratio.
??? The number of teeth on ring gear & pinion change The physical size of the ring and pinion do not change...
IMHO if you plan to upgrade to a 9" all those upgrades on the 10-bolt is money saved for the 9"
If you add up all the mods and the cost for a shop to do them to the 10 bolt.. you could just buy the 9" for the same amount.
That's actually what I have been contemplating here recently. I will have $500 in the 10 bolt just in upgrades and it still may break. However, every single person that I have talked to about a 9" on craigslist or facebook just blows me off. Have talked to over 10 people so far to no avail. So if any of you have an leads on cheap 9", hit me up.
Buy an aftermarket bolt in housing for a 3rd gen with axles (suggest 31 spline). Should be somewhere around $1000 - $1200. Should also come with backing plates to use late model GM disk brakes but don't quote me on that. Go to your local junkyard and find a 31 spline center section with a posi and 3.73-4.10 gears. Maybe in an old bronco. Bolt them all in and go racing. Upgrade to a new posi or deeper gear ratio at a later date.
Wasn't the last offering to use a Ford 9" early 80's? Slim chance on finding a 36 year old truck with a 9". Even out here in the desert where vehicles last a long time 1980's vehicles are becoming very scarce. Waiting for one to come along to buy second hand from a racing application might be easier.
Originally Posted by NoEmissions84TA
Changing to 4.10s makes the problem of the small and weak gears even worse. The pinion gets physically much smaller with this ratio.
Originally Posted by FRMULA88
???The number of teeth on ring gear & pinion change The physical size of the ring and pinion do not change...
4.10 looks pretty small to me.........
Last edited by NoEmissions84TA; 11-03-2019 at 09:34 PM.
Thanks for sharing photo. You tell people why not to run a 4:10 on the drag strip in a 7.5 and they don't get it. They look at you as if you have three heads.
to have fun with the car...save your money as sticky tires low gears kill the 7.5. with any real power.. have stacks of ring and pinons cracked and broken from the 90's nothing feels better then when ya put a 9" under your camaro that holds up to what you put to it... its sorta like playn with Small blocks and LS's then ya get a Big block! and power.. the 7.5 is a weak link.
when I post this stuff on face book..Guys snivel..and cry.. tryn to sell the 9 bolts..lmao..as a go to fix.. from the 7.5...
Last edited by articwhiteZ; 04-18-2020 at 01:24 PM.
10-17-2019, 12:46 PM
