Rear end gearing

[FE3X CLONE]

That 7.5 spent most of its life behind my previous 455. Never had an issue with it but I also never put slicks on it either.
The current 455 has a Ford 9" behind it.
I have another built 7.5 behind the 403 that's been going strong too. That one wevery used drag radials with. 1.8 60 ft's running low 13s.

 

[King_V]

Sweet. As, when my continually procrastinating self gets the 455 built, I would like to know that the 7.5 will at least live a little while. I probably will go with tires in the 235-255 width range, and NEVER slicks! I plan the car to be more a street bruiser/cruiser than anything.

 

[Bonnewagon]

Definitely go find a whole posi rear and swap that in. Don't even think about playing around with yours without the tools and the talent. Now, when you drop down to 3:23 or so, not only will acceleration increase, the STRAIN on your rear will decrease. THAT is the key! Big motors pushing dead rears just break things. My weak 7.5" 3:23 gov lock rear lived for 10 years behind a Pontiac 400 with no problems at all.

 

[GT_80]

My rear has 2.41 gears and its a 7.5" with factory limited slip- my motor has about 280 hp and 380 TQ and so far it hasn't blown up even with constant left turn drifts and some pretty big burnouts. And I get 16+mpg!

 

[ssn696]

14.67 @ 82mph SBC 400 in a 3600 lb wagon using a 3.73 Richmond gear setup and an auburn posi. There's been about 25K more miles on it in 20 years, now in another car. Use good bearings in the installation kit, and the 7.5 will survive.

 

[jacobdavis1979]

Sweet. As, when my continually procrastinating self gets the 455 built, I would like to know that the 7.5 will at least live a little while. I probably will go with tires in the 235-255 width range, and NEVER slicks! I plan the car to be more a street bruiser/cruiser than anything.

With the parts i used on paper my 350 should be about 400hp at the flywheel. I wasnt super hard on it but not easy either that rearend still kickin although ive never purposely let the tires fry that may have been a diffrent story. But my transmission was a diffrent story it didnt take long for that thing to explode on me lol But my point is if you wanna temporarily use a 7.5 ive got away with it for years! 😀

 

[King_V]

But my transmission was a diffrent story it didnt take long for that thing to explode on me lol But my point is if you wanna temporarily use a 7.5 ive got away with it for years! 😀

That's very good to know. I was hoping I wouldn't have to get a trans and a rear all at once - granted a 2.29 open rear will be . . ah . . "interesting" with a big block and a 200-4R (that would be what, a 1.52:1 effective final drive ratio? Yikes), but I can always improve on that later.... I guess I just won't be using overdrive much at first! LOL

 

[81oldsdragcar]

You could buy a Richmond Powertrax unit for 7.625. I'm not sure if you now about this unit, but you can take an open carrier and make it a posi. It's not had to install.

 

[pencero]

I would buy the 7.625 either way. They are becoming very hard to find so imagine the near future. And it already has a 3.73 in it? I have the 7.625 in my 88 and with 2.41 / or 2.56 it is very slow I would love to have one with the 3.73 instead...