i have a 68 roadrunner 8 3/4 rearend what year car would have a sure grip 355 possi center chunk that would fit my car?

Any 8 3/4 chunk will fit.

before certian memebers break out the tar and feathers...mopars never had "posis". now then, any year 8 3/4 from the '60s and '70s could have a 3.55. look at trucks, alot of slant 6 pick ups had 3.55, or even 3.91s.

ok guys set him stright for me as he just let it sink in lol
first he has a nice lil play toy he just bought and it needs some of the lil nickle dime stuff
has a nice running 383 with 260 something duration has a 2.7 something gear lol that being said it still spin the tire lol
he has no plan of ever driving it out of town and wants to be able to really light em up
told him to put a 3.91 or 4.10 in it he would really like it and the car would be night n day differance so tell evert (his name) so he dont think im blowing smoke up his ...well ya know

ralph toplescuda

What center do you have, 741,742 or 489? You can buy gear sets and swap out the gears and install a suregrip unit in what you have now. 3.55 or 3.91 will get you what you want.

It's getting hard to find good used gears anymore, and when you do they are generally going for some coin. Also, there are lots of "good" used gearsets that will run and last a long time but they howl and whine like no other. I had some 3.91's that did this and I paid good money for them years ago.

DocDiff here on the board sold me my gears (742 case) brand new a couple of years ago. For new gears, it's a hard deal to beat. Look him up

Ditto for the SureGrips.

Your question shows that you are making an assumption that is incorrect. There were no models/years where you could be sure walking up to the car that it had either a SureGrip or 3.55s. Someone is sure to point out Dana 60s in Hemi cars or something else, but walk into any scrapyard and find one of THEM!

The right answer is to remove your center section and take/mail it to DoctorDiff for a new gearset and new clutch-style SureGrip. Then everything will be right.

Also on the SureGrip name. It was ChryslerCorp's trade name for a limited slip differential. They sold at least three different units, depending on year and model, but all were called the same name. Posi-Traction is what GM called them when sold by GM. Every anufacturer had its own pet name for a limited slip.

R.

we just bought a 3.91 sure grip centersection bout a month agp for 250.00 so the still out there
i told him about a lil a100 van that i thought had 4.10 gears setting can prob buy the who van for 200.00 yank the gears and sell van for scrap for more then 200.00
he keeps telling me that he dont care about how fast it is (not a drag racer) he just wants to be able to punch it and smoke the heck out of them lol n cruise it around town just how big of a tire can you tuck up under there??? its got some 50,s on back on what i think is 10 wide rims and the is like 3 inches of clearance from tire to the leaf springs lol