posi ?'s

Hey peeps, been awhile. I bought a '65 GTO rear end awhile go for my '66 Tempest wagon. I do plan on rebuilding and using it (or rather have it rebuilt) but am having trouble deciding on what to put IN IT. Detroit Locker, TrueTrac, Eaton, Auburn, Richmond, etc. It's a 3.23 open gear unit. I'm planning on a carbureted 501 with over 500hp. This will be a weekend cruiser, freeway driving to shows and swap meets (TH400 with Gear Vendors gear splitter), and of course quick blasts on the street to keep the usual Mustang/Challenger/Corvette punks in line. I'm going with Spohn Racing control arms and their drag sway bar setup to keep the rubber on the ground. I want to use some tall gears (2.90's - 3.08's) to use the engine's torque to best advantage but what do you guys recommend for a carrier? Will this rear end fit the bill? Do I need a Chevy 12 bolt? A Dana? A Ford 9" (God forbid...)...gimme some advice fellow wagoneers!

Thanks!:confused:

 

Wish I could help. But I still remember what my dad often told me. "Son you don't know your rear end from a hole in the ground." He spelled it differently!
My 24 year old son just rebuilt his 85 Chevy truck rear and changed it to posi. Bought everything at our local NAPA. By the weekend he was towing a trailer with his stock car to the track. A few days later he was mudboggin. So much for break in!

 

my advice is go with the 9" ford i'm sorry to say. i just did the same with the rear end in mine three yrs ago rebuilt the rear with a 3:31 richmond gears eaton posi new axles ,bearings and seal and the damn axle seal keeps going bad. the ford 9" will have many more parts available and probably cheaper then the chevy after the initial cost of the rear. plus many shops already have the 9" setup for gm apps

 

The Richmond locker kit is probably the cheapest and the noisiest but I'd go with the Auburn if I was you. It is as close to the original Super Duty 12 bolt or Pontiac sliding axle as you can get. Go find an old Catalina wagon in a junkyard and take a peek under. You might get lucky. They put the Super Duty differentials in wagon with towing packages. The ten bolt GM differential has seen plenty of use with lots of power and held up but the twelve bolt is stronger. Some ten bolts from late models come with a limited slip differential installed and taller gears to boot. And don't go with too tall a set of gear either. Those long stroking ponchos love a middle set of gears 3:23-1 or even 3:55-1. The Tempest will love em and they work well with the 400 and the overdrive. I run an AOL in my 67 Futura wagon and I tach 2000 RPM at 60 MPH and I have 3:88's. Lower gears hurt you in overdrive when you're climbing hills or towing Keep your power torque range operable with the car in overdrive
Good luck.
Dave

 

Hills and towing won't be an issue as I live in Florida and don't own anything to tow. I do have an old 1963 IMP Apache that I will restore. It's an old 16' fiberglass boat, will handle about an 85hp outboard. Real light, like grampa's old lake boat. But that is way down the road. What mods will I have to do to get that B body rear end under an A body frame? What about a GP or Bonnie rear end?

 

if you modify any rear do the 9" parts are easily available . wish i had done it 3 yrs ago when i rebuilt the rear i have now. today you can buy the 9" housing to fit most gms for under a grand new usually complete in the ball park of 1800-2500 depending on options. wasn't much cheaper to build my chevy rear

 

Dang. Everybody sez Ford 9". I want to try and keep it all Pontiac ya know? I don't think I'm asking too much from a 455 punched out to a 501 to deliver over 500 hp. That should be fairly easy. A stout TH400 with a Gear Vendors unit on the end should be able to easily handle the torque and give me fat acceleration no matter where my foot is. Keep in mind I'm not a know it all but I'm learning the Pontiac rear end may be the weak link? I'm not racing the damn thing, but I don't want to shred it to shavings if I want to go from 30 to 100 either. Seems it's always a mild overtune or nasty strip car. Isn't there a somewhat happy median? Did Pontiac make any stout 12 bolts for the A body? Last thing I want is a killer engine, killer trans, and a weak ass rear end that may detonate. A Ford? Really???

 

its just economics ,ford 9"s are easily built to run for hours and hours under 750-800 hp in nascar. on the power tour rousch/yates garage had dozens and dozens of ford 9" parts. . nascar rears could easily survive 500 hp

 

As much of a GM man I am, the Ford 9" or 8.8" is a proven stout rearend. That being said my dad is running a GM 10 bolt 8.5" with upgraded Moser axels in his Malibu with a 502. It is 502 hp and 565 ft.lbs of torque backed by a turbo 350 with a 3200 convertor. Granted it has only been a little over a year but it has been launched on a sticky set of et street tires 8 or 10 times hard enough to get the driver side tire off the ground and driven only a little over 2000 miles in a year but it has held up so far. I would also say that is the weakest link in the car and when it comes time for a up grade I would probably go with the FFF...FFOO...FFOORR....FORD rear even though it is hard for a Chevy guy to say!

 

What did you say 1tire? :confused:

 

I think he dropped an F-Bomb.

 

I try not to use the "F" word too often, especially around my dad!

 

First On Race Day boys and girls

 

If my highschool buddies ever used Ford bits in their GMs, they certainly would have kept it secret. That would have been 1st degree sacrilege, back then. Nowadays, everyone is forced to merge into a big happy family. You know, I once read in that P.I. Pontiac forum, a few years back, that when the Saginaw trannie division went on strike, back in the 60's, GM ended up buying Ford surplus which weren't bad.
If it's an item which isn't going to get seen from the outside, why not go for it? It's no different than updating some '51 Chevy 6-volt electrical system by converting it over using a 12-volt generator. Without taking a close look, the difference shouldn't be noticible and if the vehicle isn't going into a museum, it doesn't matter and shouldn't devalue the car. If I replace a gear reduction drive in a Bosch drill with a Black & Decker, you might be able to hear a slight difference. But, you'll never spot it visually

 

Hans gave a great reply. Seems like the F----- RD rear end has been used a lot for it's strength and most people have no idea what's up your rear!