Thread: ? about rear end

Tweet

I have found 2 rear ends for a vega that I am building.

One is a Moser 12 bolt allready sized for a 72 vega and set up for ladder bars. It has 5/8 studs, 30 spline strange axles, 30 spline spool,and the big yoke.The guy also has new bearings and Backing plates w/ brakes but no drums¦ 900 obo also needs new gears. Not very excited of the drum brakes, how much would swithcing to disc change overall measurements?

The other is a ford 9" with strange 35 spline axles, strange 35 spline full spool, A comp. eng. back brace that needs to be welded on, strange aluminum center and pinion suport. The axles have a 5x5 bolt patern with long studs. The rear was narowed 3 inches to fit under a truck. He mounted the rear end but never finnished the truck so it just sat there. It has the disk brake brackets on it and will accept ford continental rotors and calipers. This one is 1000 dollars. plus shipping and would have to be narrowed.

I hear 9" are great because of their ease of gear changes. Chevy 12 bolt are more difficult for gear changes but operate with less friction. Which of these would be a better deal? The vega will make 600 horse on the bottle in the 1/8 mile.

Thanks for any help.

I prefer the 9" just for the gear changes... Never have broke one. The one in Rog's Comet has probably 500-600 passes on it with only 1 bent pinion, and the gear company replaced that gear set for free. 12 bolts are also a bit more difficult to set up IMO. Parasitic horsepower loss is minimal, maybe 5 or 6 horsepower. If there good enough for 90% of the door slammers at the drags, should say something about which is preferred and their durability.

If which ones are good enough for 90%?

setting up for disc brakes will not change anything on the rear ends width. tha axles are a set item and do not move. if you are looking at new gears and disc kit, look at about 1000 to 1200 bucks extra on top if the 900 for rear end cost. 9" over 12 bolt if you have a choice, but the 12 bolt is fine if you already have one. as far as gear changes being easier, yes much easier with a 9". but once you build the car and select proper 1/8 mile gear. its not like you will be changing gears everytime you hit the track.

Originally Posted by BigTruckDriver

If which ones are good enough for 90%?

9" Fords...

As for the disc brakes, I have an "alternate option" for putting disc brakes on the 9" Fords with 4 1/2" bolt patterns, cheap and easy...

Ok what your alternate option for disc brakes? Also I see some 9" have the pinion centered , what the purpose of this? Is it for certain style of racing? That means one axle is shorter than the other...

Also I am planning on useing a 10" tire and a 12" tire in the future. Would it be ok to set up the rear for the 12" tire and use spacers for the 10" I am planning for currently?

Originally Posted by BigTruckDriver

Also I see some 9" have the pinion centered , what the purpose of this? Is it for certain style of racing? That means one axle is shorter than the other...

I'm not sure I've ever seen a stock 9" rear that didn't have a centered pinion. The pinion gear is offset to the ring gear which is in the center of the carrier. In order to have a straight floor tunnel, the entire carrier portion of the axle is offset to put the pinion in the middle of the car/truck. This naturally ends up with one axle shorter than the other. Could it be you're asking about having the carrier portion of the axle housing centered, which would in turn make the pinion offset relative to the overall housing? If so, it's most often done for appearance.

Just get with your local dirt track supply house, or Speedway... They sell a bracket to weld on the housing to use GM metric calipers and rotors on a 9", about $300. You can get everything other then the brackets at most any parts store and do it all yourself for a bit less... The package from Speedway is probably the easiest and quickest way....

I don't like using spacers myself, I'd just get wheels with different width and backspacing to run the bigger tire.

Pinion centered puts the pinion in the center of the car, where it should be, and uses different length axles....

^^^ I think this is to ensure the bearings in the u-joints get used all the time. The big three had different approaches at achieving this, GM offset the rearend to one side, ford offset the rear lower than the trans, and mopar offset the motor to one side... this is what I hear and if any of it is wrong, I'll be happy to hear it...

-Chris

BTW: Ford 9", GM 12-bolt, and Dana 60(?) should all be able to handle the power for a Vega.

-Chris

as much as i hate to say it dave is right THE ford 9 inch cut and center the pinion and No spacers and go . i have did more with less with the ford 9s you do not have to do much to them to take alot of power look at the nascar stuff on ebay good deals on very good parts

Guess its looking like a nine. you guys think this is worth 500 dollars? Dont know about the centered pinion though...

9" Fresh housing with new 1/4" DOM tubes 1/2 big ford bearing ends. 36 3/8" wide housing, 41" wheel flange to wheel flange without the rotors on. Housing has internal gussets,centered pinion.Used 35 spline Strange axles 5 on 4 3/4 5/8 studs . Housing with axles,bearings,studs,no lug nuts or spacers

Heres another ,9 inch rear end out of a 94 mustang cobra. The guy wants 650 for and lives around the block. Is it worth it?

Unless it was changed, a '94 Mustang would have had an 8.8 rear end......