Built rear end?

[einehund]

I'm moving back to the U.S. which means I can go back to drag racing. However, i love corners at speeds as well. Currently have a bone stock rear end with some LCAs. I think i may have lightly bent an axle while playing around, so i am thinking just to get a built rear. I'd like something that i can reliably beat on repeatedly on the strip, but i don't want to compromise putting the power down in corners. any suggestions on what i should ask a shop for in terms of axles, differentials and things like welded tubes? Also thinking that i want to go from 3.55:1 gears to a better ratio, but not sure between 3.73, 3.90, or 4.10s. I had 4.10s in an old mustang, but it didn't have 675 hp at the wheels!

 

[HillbillyHotRod]

If you really want to beat on it and not worry get a 9 inch.

 

[merkyworks]

^+1 if you want to not worry about rear a 9 inch best. I think @biminiLX has a built 8.8 with all the trick and goodies one can do but IIRC he still has a few issues here and there.

OP are you thinking of changing gears just because drag racing or do the 3.55's have to much RPM hang time for your liking?

 

[einehund]

Honestly, the 3.55s are fine. I'm used to them. I just don't think i'll ever be on the Autobahn anymore so 200 mph isn't necessarily needed. A little extra oomph would be okay with 3.73s. I was just thinking if I'm redoing the rear, it would be an opportune time to do the gears.

I am hesitant to do a 9 inch as i am not pushing enough power as biminiLX is and the 8.8 should be able to hold it without sacrificing road course manners that the 9 inch might.

 

[merkyworks]

So depending on how much traction you get, 3.73's can have issues with whining.

I say this cause my power level is similar to you and my rear end is stock on the inside with 3.73 and 40k miles on it, never been to drag strip but have done dig races. When I installed TA, WL, LCA with near solid bushings and 315 tires the gear whine was minimal/very livable but the upgraded traction over this past year has allowed the rear end to distort and something isn't happy (backlash or bearings IDK). Sometime soon I got to get my rear end rebuilt with new gears cause it is whining very loudly and I'm going to rebuild with 3.55's in an effort to help reduce any whine potential. Other users with 3.73's have had similar issues where the rear end is quite and then after a trip to the drag strip the rear end whines.

Heavy car weight and lots of torque make rear end distortion very likely. Things like welding axle tubes to housing, installing/welding a rear end brace, installing a rear cover with gridle, upgrading main cap from bolts to studs or changing cast iron main caps to billet main caps are all good ways to help.

 

[Catmonkey]

I'd probably opt for the 33 spline Eaton True Trac and custom axles. Getting rid of the c-clips with the 9" axle ends would probably be best, but would run up the cost. I would have similar concerns with the 9".

 

[Klaus]

You are fine keeping 8.8. Weld the tubes and swap your axles. You should be fine with 28/31/33. Tru trac w/ 3.73s is what I went with. You might think of a torsen if you plan on tracking it. UCA/LCAs and panhard or watts link.

 

[RedVenom48]

I'm moving back to the U.S. which means I can go back to drag racing. However, i love corners at speeds as well. Currently have a bone stock rear end with some LCAs. I think i may have lightly bent an axle while playing around, so i am thinking just to get a built rear. I'd like something that i can reliably beat on repeatedly on the strip, but i don't want to compromise putting the power down in corners. any suggestions on what i should ask a shop for in terms of axles, differentials and things like welded tubes? Also thinking that i want to go from 3.55:1 gears to a better ratio, but not sure between 3.73, 3.90, or 4.10s. I had 4.10s in an old mustang, but it didn't have 675 hp at the wheels!

Welcome home sir!

It may cost nearly as much as a 9" to really beef up an 8.8. Youre talking parts and labor. If you really want to build the 8.8, it makes no sense to do anything lest than a Strange S-trac 35 spline diff, 35 spline axles with 9" ends welded on. Add to that the labor needed to weld the axle tubes. If Im honest, thats not enough for an 8.8" and you need to add an axle housing brace to the assembly for strength. Ford G2 Diff Cover and Moser (ARP) diff cap studs to keep the Diff and ring gear from moving around under high load.

I suppose the real issue is most of the limited slip diffs that are worth a shit to install for drag racing need C-clip eliminators. C-clip eliminators are good, but dont have the strength and are known to leak compared to 9" ends.

By the time its all said and done, a Strange 9" might be reasonably in the same ballpark. Plus, you can set the car up with a spool for drag nights, and for general street use/ road racing you can swap the pumpkin with a performance diff set up.