OK, everyone here me out. I have a 91 Z28 with a swapped in T5. I am currently running a 3.23 posi stock rear end. My buddy is gonna be parting out a his 89 formula, bout all thats worth having is the rearend and some other stuff. Anyway hes got a 10 bolt with moser axles, auburn posi, and a fresh set of richmond gears 4.10. The bad is that a. I want to run a 3.73. b. The rear end is a drum brake rear like I already have. The rear end previously had 3.73s that were set up incorrectly that broke. My car currently has bolt ons currently, but will ultimaltly have vortec or etec heads, cam and stealth ram on it. What kind of RPM would I turn at lets say 60? Whos done it? would you do it? I know I can pick up the rearend for 300, and maybe 200. Would you guys pick it up or just buy a 3.73 gear set as planned.

 

going from 3:73 to 4:10 would be around a 370 rpm fifference

so say u went 60mph @ 2,400 rpms with the 3:73s with the 4:10s @ 60 would be at around 2,800

so its not to big of a difference i would choose what would work best with ur planned future mods

 

I have a 9 " ford with 4:56 gears, car revs at 2150 at 70mph with my factory t5

 

In most cases with 26" tires, 4.10 would be too much gear.

 

Putting a 4.10:1 behind an L98 is a definite mistake unless you swap to an HSR and a 200-4R. A T5 / 4.10:1 combo might work behind an L69 with porting, cam, intake, headers and exhaust.

 

3.73 good for the street.. 4.10 more for drag strip..

 

What about 4.56 gears behind a t-5 with 27-10-50-15 hoosiers?

 

As I posted above I run 4:56 gear on the street with a 30 tall tire, if I would have known that my RPM's were so low at highway speed I would have put in a 4:86 set of gears

 

Does it feel really good? Did you have to modify anything for the 4.56 in a 7.5? I've heard people mention that before!

 

I am running a Ford 9 inch rear end

 

Yeah im not capable to run one of those yet!

 

IMO I would go for it and just keep both rear ends. Then you can always switch back.

 

If you plan on making a bunch of power or launching hard, you
might want to stick with the 3.73. General consensus here is that in the 10 bolt the 4.10 gears don't last very long.
On the other hand, the whole rear with the Moser axles and gears would be a pretty sweet deal for 200 bucks! I would think your current combo wouldnt have the rpm range to spin to 6500 rpm which would be ideal for drag racing, but it Would be a blast to drive on the street!
My vote would be to use the 4.10 setup and see how you like it. If you feel you're using too much gas, you shouldn't have any trouble getting your money back out of it. Just don't be too hard on launches! That's what kills ring gears.
What height rear tires do you have now?

 

Well I'm currently running a 4.10 and its good dont get me wrong. But I want a little more jump out of the hole. I'm really considering swapping to the 4.56. Is a 4.56 harder on the drivetrain parts? I can't seem to find an answer!

 

This is just a strip car! Occasional trip to the car wash a mile down the road is it. It pulls to 6500 but I never go that high. Shifting at 6k. I've had the 4.10s in there for over a year and this past season I put over 230 passes on the rear. Dumping it every time