My 65 has a 10 bolt 3:08 rear that was behind a 6 cylinder for only 45,000 miles. Should I add a posi and better gears or upgrade to the correct width (64 & 65) 12 bolt? I'm planning on running a small block and 4 or 5 speed. Just crusing with an occasional burn out. Will it hold up?

Yes it will hold up fine. I have the same rearend in my 70 behind a beefed up 350 that's putting out close to 380hp. The 3.08 gears are not the greatest for hole shots off the line but they are perfect for cruizing and highway use. With a small block it will be hard to destroy a 10 bolt. Unfortunately they don't get any credit compared to their 12 bolt big brother.

Is it an 8.2 inch or 8.5 inch? My brother ran a very healthy small block in front of his 65 Chevy II rearend, but it was a 283 setup from the factory. He did break the yoke powershifting second gear once. I just rebuilt my 8.2 for the street. I hope it holds up! Small block, 4 speed, street tires. No slicks at the strip, that would be pushing it even with the 355. Good luck graemlins/thumbsup.gif

I believe my 10 bolt is a 8.2"

if you're going to throw money at one build the 12 bolt... the posi & gears cost the same... I'd think twice about spending 600 dollars or so on a 10 bolt ... as for being able to live on street behind s/b the 10bolt with street tires will have no problems

BondoBob,

If you rebuild ythe 10-bolt with a new posi unit (I'd also get new axles for under $300), it should be fine...

The 8.5 rearend didn't come out until 1972 model year, so they are not common (since 64-72 Chevelles have a unique housing).

While it should be fine, personally I would look for the 12-bolt core. The cost of rebuilding will be almost the same whether a 10-bolt or 12-bolt, its only the additional cost of finding a core housing to work with...

By the way, a 12-bolt from a 1968-1972 Chevelle will bolt right in (and they are alot more common-cheaper$$$ and easier to find)... The only difference is the overall widthdifference which moves the wheels/tires out about an additional inch on each side (all brackets are in the same location)... If you tire clearance allows the additional 1 inch, this will aid in you search...

I would estimate $1100-$1200 to completely rebuild the rear, including axles, posi unit, new gears and bearings and labor...

I have been running a BOP 10 bolt posi 3.31 for years,,,,,no problem for a street cruiser SB that still shows her stuff on occasion!! You should get years of great service.

I've gone through three early model 700R4 transmissions on my 8.2" 10-bolt with an Auburn Pro posi unit (they didn't offer an Eaton when I rebuilt the rear). I beat on it kind of hard fairly often. Never tried it with slicks.

I'm hoping the latest transmission will hold up longer.

I'm running a smidge over 400 lbs of torque through it now, and will hopefully get near 450 later this year when I finish the 383 "stump puller". I'll be prepared for it if the rear breaks, and you guys will be the first to know about it.

Thanks for all the replys guys, I'm sticking with what I've got and add a posi.