25thannivZ28

In the link in my signature "Launch vs. Mustang" I ran an 11.9 @ 117 ,with a 1.744 60' time. It had 2500 - 2800 stall converter. I blew 3rd gear on that run (it slipped terribly and over-revved 2-3 shift). You can hear the "Over-rev" in my acceleration video.

This year, I did no motor mods, only transmission (700R4 still). Upgraded to a 3200 - 3500 converter. For the short period I got to drive the car last year with my new transmission/TC combo, it was a completely different car for not just taking off, but when I punch it going 40mph it has a definite seat-of-pants difference in whip-lash effect.

I don't know the HP#'s that I am running currently. I would estimate high 300's rwhp (modestly) Maybe more realistically low 400's.

Now, my question is this. How many of you think that my mostly factory 10 bolt rear-end will hold up to this? Its all factory, other than the Richmond Gear 4.10's ring & pinion that replaced the 3.23's.

I'm requesting opinions to gauge how much of a priority I should put on installing a Ford 9" or 12 bolt. Thanks for your feedback.

Night rider327

iTrader: (13)

With a 1.7x 60' time you are on borrowed time with the rear end. At around the same 60' time I started noticing some clunks/whine with mine, then in the mid to high 1.6's it broke.

Broke ring gear, put another parts car rear end in it and pinion broke on it soon after.
Both rears wasn't stock either. Yukon axles, power trax lock rite locker, TA support cover, timken bearings.

The locker and axles wasn't hurt though.

I swapped to a ford 9" rear and gave my dad my 10 bolt axles, locker, and cover and he's been running those for the past 6 years or so.

Pro Built Automatics

To make the 10 bolt hold up. First do not make the transmission shift hard. Use one of my modified TransGo Shift kits to achieve this, if yours shifts too hard. The rear end support cover is good. Install a steel cap on the ring gear side and eliminate the crush sleeve and install the solid spacer if you can. Run a little more preload, and run the minimum ring gear to pinion gear clearance. Make sure the contact pattern is good. I do not like Richmond gears as they are noisy in most cases. The 4.10's have a smaller pinion than 3.73's, 3.42's and 3.23"s, so that makes them weaker. It is the pinion size that helps keep these rear ends alive. What gear ratio were you running when you ran the 11.9 ET? If it was the 3.23's, then you might put them back and the rear end could last into the low 11's, and that is the best you most likely will see out of this setup. They do not eat any horsepower and that is the one good thing about the 7.5" rear end.

25thannivZ28

It was with my 4.10s, they've been in for 7 years and about 40,000 miles. Thanks for that info

25thannivZ28

I was well into 4th gear at that 117 mph. Maybe it's time to switch to numerically lower gears