i have 489 case open... how/what do i need to make a sure-grip?

[340plot]

i have a 489 cased center section in my 8.75. it is a open, and i am sure it has a highway gear. what do i have to replace to make it a posi unit, and i am looking to make it like a 3:73 i think woud be nice.

any companies out there that seel a full unit? or ..if i buy all the parts to put in my case, do i still need to send it all to someone to set it up or would it be a drop in thing?

 

[RustyRatRod]

You can buy a Powertrax Lock Rite and convert what you have to a similar unit to the Detroit Locker. It will operate in much the same way. It will not be a posi. It will lock the axles together under power and release them to go around a turn. They actually make an open carrier much stronger because they eliminate the spider gears. They are pretty nice and will handle around 400 HP possibly a bit more.

 

[wish4hemi]

Check Randy's Ring and Pinion, Summit Racing, or Jegs for parts. You should just need the Sure-Grip unit and a new ring/pinion set. It is definitely not a "drop in thing". It will need set up for backlash, preload, etc. The factory Mopar manual does a nice job of explaining it. I did mine myself with no prior knowledge; just a Mopar service manual and a press. If you're not up to doing it yourself, you can buy a third member pre-set-up from Randy's Ring and Pinion, but they're pricey.

 

[340plot]

yea, too pricey for me. but it seems that noone ever sells 3:55 or :71 anymore. lol

 

[340plot]

another question is, would a 72 8.75 340 car have a small yoke or large yoke. there is a suregrip that was just listed for sale, but i do not know if it will work with my driveshaft.


the cups on my universals are 1.06" i believe,,,,,,small or large yoke?

 

[horsehead]

another question is, would a 72 8.75 340 car have a small yoke or large yoke. there is a suregrip that was just listed for sale, but i do not know if it will work with my driveshaft.


the cups on my universals are 1.06" i believe,,,,,,small or large yoke?

It will work.If the yokes different count the splines and get an aftermarket yoke to fit your application. Many vendors sell them.

 

[RustyRatRod]

With the Lock Rite you don't even have to worry about gear setup because you never take the gears out. Just FYI.

 

[needsaresto]

You can buy a Powertrax Lock Rite and convert what you have to a similar unit to the Detroit Locker. It will operate in much the same way. It will not be a posi. It will lock the axles together under power and release them to go around a turn. They actually make an open carrier much stronger because they eliminate the spider gears. They are pretty nice and will handle around 400 HP possibly a bit more.

Surely they can handle more than 400 h.p! A good detroit locker should hold up to a big block...