[gearjammer38]

hey everyone its been a while since ive posted on this site but ive always recived the best help off here so ill always turn to you guys.

im working on building my first rear end for my 70 nova, im going to be swapping in a 73 8.5(which i already own). im looking for information on what kits i should use also what posi unit that would best suit my needs.
the car has a 88 305 in it,and a M20 tranny, the hottest engine this car will ever have is probably a 383 or somewhere along those lines so im not looking to build a big budget bulletproof rear here. just a nice one that i can have fun with smoking tires once and a while. the car will almost never be on the track, (maybe once for Ghits and Shiggles) nor will it be traveling long distances on highways, an hour or so at most. its probably just gonna be a Friday night stoplight to stoplight show off. im just trying to get ideas of what kits to buy and also what posi, i'd like to run 4.11 gears or so with maybe a 28" tall tire if it will fit. ive done some research on installation and whatnot but im really looking for advice here on how to build a rear to suit my needs. also i will need axles too
should i buy a kit like this? will it have everything i need?

Summit Diff install kit

how about these axles? i dont think ill ever be running hard-hooking slicks or launching at high RPMS

superior axle kit

im not set on any of these sites/company/brands, their just ideas to try and help everyone understand what im ramblin about.
also to anyone else looking to do the same i found these sites extremely helpful

http://www.drivetrain.com/parts_cata...tructions.html

http://www.thirdgen.org/techboard/tr...axle-gear.html


sorry for the novel, i just wanted to give anyone as much info as i can.any help will be appreciated, thanks all.

[ericnova72]

Check out Yukon gears, axles and Yukon Duragrip positraction units. One good source is Randy's Ring and Pinion.

Avoid Auburn posi units, and stock GM Gov-Loc units from the 1980's. Factory Eaton posi units from the 70's are good if you can find one, but they can be worn out and need new clutches so watch for that if you do find one, as rebuilding it will add to the cost.

[big gear head]

I have built many of these rear ends with the 30 splin Eaton Posi and 30 spline Moser axles. I use Yukon gears and installation kits. This will give you a good strong rear end that's ready for future power upgrades. One suggestion that I have with the 8.5 rear ends is to weld the axle tubes. The plug welds on these rear ends are not very good and they have been known to break loose and let the rear end twist up. Welding the tubes is not a simple job. It requires nickel rods or wire and skill for welding steel to cast iron, but it's worth it. You don't want the drive shaft and pinion yoke sticking up through the floor under the rear seat. If it will never have slicks on it and if you have wheel hop completely under controll then you can probably skip this. Read this before trying to weld the tubes.
http://www.nastyz28.com/forum/showthread.php?t=18890

This is one that I did with nickel wire.

[gearjammer38]

Originally Posted by ericnova72

Check out Yukon gears, axles and Yukon Duragrip positraction units. One good source is Randy's Ring and Pinion.

Avoid Auburn posi units, and stock GM Gov-Loc units from the 1980's. Factory Eaton posi units from the 70's are good if you can find one, but they can be worn out and need new clutches so watch for that if you do find one, as rebuilding it will add to the cost.

i actually have a GM Grenade-Loc in my basement, i bought it for $20. after doing some research on it i decided to not use it. im looking to buy a newer posi off summit or some other company, im just looking to see whats the best one to go with, again i dont need a top-of-the-line one, just one to suit my needs

[gearjammer38]

Originally Posted by big gear head

I have built many of these rear ends with the 30 splin Eaton Posi and 30 spline Moser axles. I use Yukon gears and installation kits. This will give you a good strong rear end that's ready for future power upgrades. One suggestion that I have with the 8.5 rear ends is to weld the axle tubes. The plug welds on these rear ends are not very good and they have been known to break loose and let the rear end twist up. Welding the tubes is not a simple job. It requires nickel rods or wire and skill for welding steel to cast iron, but it's worth it. You don't want the drive shaft and pinion yoke sticking up through the floor under the rear seat. If it will never have slicks on it and if you have wheel hop completely under controll then you can probably skip this. Read this before trying to weld the tubes.
http://www.nastyz28.com/forum/showthread.php?t=18890

This is one that I did with nickel wire.

thats one h e l l of a good job. was there a jig involved at all? or was controlling the heat/cooling enough to keep it from warping? i also sent you a PM

[cranky1]

Any time you weld on a rear end, you're going to get some movement. As for a jig, I don't weld with mine in place but I do stick it in to see which way it moves then weld accordingly cause if you weld with the jig in place, you might end up having a hard time getting it back out. And if I'm welding on new bearing housings....they are welded last.

[gearjammer38]

Originally Posted by cranky1

Any time you weld on a rear end, you're going to get some movement. As for a jig, I don't weld with mine in place but I do stick it in to see which way it moves then weld accordingly cause if you weld with the jig in place, you might end up having a hard time getting it back out. And if I'm welding on new bearing housings....they are welded last.

can you go into more detail about this? whats on the inside? is that just a thick bar? does it run the entire length of the housing?

[ericnova72]

I can help you here. I've made one.

Bar is round stock, 1-1/8" to 1-1/4", I used T-GAP shafting(Turned, Ground, And Polished). You then need to machine steel or aluminum "pucks" to go in place of the carrier and axle bearings that have a hole the size of your shaft through the middle. Once the carrier bearing replacement pucks are placed in the housing and the rear caps installed the bar is placed through the housing. Then put the axle bearing pucks in the housing ends and slide them onto the main shaft. This way all the bearing bores are kept in alignment. Be sure to align the axle bearing ends before welding so the brake cylinder bleeders will end up at the highest point when the axle housing is in the car.

[gearjammer38]

Originally Posted by ericnova72

I can help you here. I've made one.

Bar is round stock, 1-1/8" to 1-1/4", I used T-GAP shafting(Turned, Ground, And Polished). You then need to machine steel or aluminum "pucks" to go in place of the carrier and axle bearings that have a hole the size of your shaft through the middle. Once the carrier bearing replacement pucks are placed in the housing and the rear caps installed the bar is placed through the housing. Then put the axle bearing pucks in the housing ends and slide them onto the main shaft. This way all the bearing bores are kept in alignment. Be sure to align the axle bearing ends before welding so the brake cylinder bleeders will end up at the highest point when the axle housing is in the car.

so ive got to cut the end of the axles off?

[ericnova72]

Originally Posted by gearjammer38

so ive got to cut the end of the axles off?

No, it isn't necessary. I didn't think about that fact as I am always using mine to either narrow the housing, or removing the stock axle bearing ends and replacing them with the common Big Bearing Ford 9" end.

The BBF housing end is the most popular for racing, gives you a big bearing pressed on the axle eliminating the need for C-clip eliminators on c-clip axle retention rear ends like 10 and 12-bolt GM and 8.8" Ford, and has the most options for disc brake conversions.

If you are just using it for checking a housing during and after welding you just need pucks for the carrier bearings and to fit in place in the stock axle bearing ends. Put the bar through the two installed carrier bearing pucks and then use the axle bearing pucks to confirm the alignment of the ends by sliding them over the bar to meet up with the factory housing bearing ends.

My alignment bar is about 6' long, so I can make nearly any width rear axle needed for hotrod cars and trucks.

[big gear head]

http://mittlerbros.com/rear-end-narrowing.php This is the housing fixture that I use now. I used a borrowed one that was made by a tool and die maker for years and then decided to buy my own. I use it to check the housing, but when welding the tubes to the center casting you don't get much movement in the tubes. I weld about 1 1/2 inch on one side and rotate it to the other side until I get all the way around. I was a DOD aircraft certified welder for about 10 years, so I got pretty good at welding.

[gearjammer38]

thanks for the help everyone, but i don't plan on narrowing the rear at all or changing to ford 9" ends, this will all be done in my garage by myself so i want to keep it simple and not get over my head. im still a little confused on how to make the "pucks" can anyone post pictures?

[big gear head]

Here is one from the old fixture that I used. They are just round steel that fits the ID of the housing end or bearing bore and the OD of the shaft.

[ericnova72]

Originally Posted by gearjammer38

thanks for the help everyone, but i don't plan on narrowing the rear at all or changing to ford 9" ends, this will all be done in my garage by myself so i want to keep it simple and not get over my head. im still a little confused on how to make the "pucks" can anyone post pictures?

This will require a machinist and a lathe to make them. Round stock turned to the proper OD to match the OD of the bearing race, then drilled and reamed or bored hole through the center match the diameter of your center bar. Mine are 1-1/4" thick.

Like a hockey puck with a hole through the middle, and the outside turned to the size of the bearing bore it is going into.

[gearjammer38]

Originally Posted by big gear head

Here is one from the old fixture that I used. They are just round steel that fits the ID of the housing end or bearing bore and the OD of the shaft.

that picture helped alot, now i understand what you mean by pucks. i assume you made similar ones that bolt into the housing?