hey guys/gals i am basically rebuilding my whole car from outside to inside, its a 89rs and when im done with the motor i should be making in the range of 400-500hp & 395-450ftlbs (i know its kinda widespread) well anyway i was wondering if i would need a 9in rear end. if i can stay with the 9 bolt i was planning on running a 3:73 with posi. what do yall think, it wont be a daily driver by anymeans and it might see the track a couple of times a year. also if its no way possible to do it with a 9 bolt what the cheapest way to acquire/build a 9 in.

 

Need more info... Is it an auto or a stick? Do you plan on using slicks at the track?

 

There is no real "cheap" way to install a 9" into a third gen.

The best and easiest way is to buy an aftermarket bolt in housing with axles. You then supply the center section and brakes.

A complete, ready to bolt in, aftermarket 9" for a third gen is around $2500

Because of the torque arm mount, there are no junk yard 9" diffs that will be a direct or easy swap.

 

in my opinion you'll be fine on a 9-bolt... I could see if you plan on racing it constantly but a few times a year you'll never break that 9-bolt.

 

ok, its an auto, and i plan on useing dot slicks if not full slicks the 1-2 times a year it might see the track. so if the 9 bolt would be ok what do you think i should do to toughen it up? thanxs

 

I ran high 11's with a stock 3.27 geared 9 bolt. 1.7x 60' times with slicks. Never had a problem. I switched to a 10 bolt when I wanted a better gear ratio and got down into the low 11's. I swapped to a 9" when I installed a transbrake.

 

sorry i kept saying 9 bolt because i was thinking 9" ford but i meant 10 bolt (stock rearend right?) any does that change anything could i still be ok with that?

 

i've been 1.64 to the 60' on a 10 bolt without too many issues. biggest thing is getting the case flex out of it. run a solid pinion spacer when you rebuild it (they are available from Thunder Racing.) and an aluminum diff cover with preload bolts and you'll be fine well into the 1.5x range. there are some guys running consistant 1.4's with some high 1.3 60's, though i can't promise you that'll happen with yours. 87 T/A comes to mind. but a 1.3x 60' is good for low low 10's...i doubt you'll be getting there with 400-500hp...that's like 650hp range.

 

- I've been 1.66 60ft, consistent between 1.66-1.69 on my 10-bolt. It's got moser axles, a detroit tue-trac, motive 3.73's and a DTS cover. No solid pinion spacer yet, but I'll probably be trying my luck with either a 4.10 or 4.56, so the solid spacer'll go in then.
- To launch I side-step the clutch at 5k.

 

save your money, run the 10bolt till it breaks, then swap over to the 9" or a 12bolt.. your choice... another option is the ford 8.8 rear, but thoes are harder to come by.

investing in a 10bolt for drag racing is like investing in 305 specific parts... sure they help you now, but if you're ever going to do anything fast, you're just going to throw it away anyway.

 

ok thanxs for all the input i think i will do what many of you suggests make it stronger with solid pinon spacer, some-sort of posi, stronger cover, and run er' till she breaks. thanxs again.

 

8.8 harder to come by than a 9"? I watch 8.8 get crushed all the time, I have a hard time finding 9" take-outs(aftermarket stuff makes this kind of irrelivant, but I'm cheap) - an 8.8 would take a custom tq arm also....

 

ok, im seriously curious about this now.

so far, ive recently replied in three ford 9" threads... in all 3 you came in with something to say.
but you dont have a 9". and from what you've been saying, it greatly implies to me that you've never even worked on a 9" setup for a third/fourth gen fbody.
in another thread, you're talking about your 10bolt.. beefing it up, ect.. so that tells me you either arnt a drag racer, or you just dont have experience with fast fbodies that need this sort of thing.
so why do you keep replying to threads like this? go out, DO the stuff, THEN come in here when you have some experience with doing it.




all that said, you answered your own question.
the reasons its hard to find a 8.8 for a stock suspension Fbody, is because only a handful of people make them.
so you're either left with making one yourself.... and if you can do that, you wouldnt be in here asking stupid questions... or you need to find one of these somewhat rare 8.8 setups... i only know a few guys running them. all were made by the same shop. the rest ive just seen online from a few other shops.

ALL of them use the STOCK torque arm, or an aftermarket equivalent.. you dont NEED a aftermarket torque arm.. part of building the housing is welding the mount to the cast pumpkin.. a PITA for sure, and yet another reason why everyone doesnt do it.

 

I haven't messed with an 8.8 other than being around my buddies 12 sec stang. - should have said I thought it would take a custom tq arm.
- We run a 9" in a bbc 81 C10 "pro street" truck that I set-up and installed with a 3rd gen style tq arm suspension. (we meaning a buddy that owns it and me who built the truck) It is a stock ford 9" that I built mounts and a custom tq arm for. - also running a 9" in several outlaw drag cars that I help with/work on.
- Helped install a 3rd gen moser 9" in another buddies 86 Z28 drag car. I built the tq arm for it, that's why I never comment on factory replacement tq arm bolt up issues.
- As I just replied in another post, I only have the 10-bolt because it was free, built in its current state. I'm gonna go ahead and put a solid pinion spacer and axle tube braces on it when I swap to either a 4.10 or 4.56 gear and if it breaks, then it breaks and I'll put a custom 9" in. My car runs 11.7's at around 125, weighs 4001lbs w/o me and I side-step the slutch at 5000+ for 1.6X 60fts. Yes, I'm sure the 10 will give someday, but so far it's done good.

- This is not an attack, just stating my knowledge and my reasons.