I currently have a 70 GSX Stage 1 Automatic with factory 3:64 8.2 Rear end. Its really no fun going on long cruises with this rear end in it. I bought last summer a 71 8.5 rear end out of a skylark and had it all redone with a posi and 3.08 gears but have yet to install it in my GSX. I have 15x8 Buick rims that I purchased from Specialty Wheels for the rear of the car with 295-50/15's BF Goodrich Radial RWL TA's mounted on these rims and currently with the 8.2 rear end I have 1/2 inch clearance between the tire and the inside fender lip and I did not have to cut anything on the rear chrome wheel well molding or the fender. There is no rubbing whatsoever. I was concerned that if I put the 71 3.08 8.5 rear end in that I might not still be able to get these big meats back in the wheel wells so tonight I took off rear tires and wheels and measured with a square the exact width of the 3:64 8.2 rear end with alum. drums (which are slightly thicker than the stock steel drums but much lighter) and I measured exactly 61-1/4 inches. I then took off the alum. drums and put them on the 71 3.08 posi 8.5 rear end and then measured it also and came up with (YAAAA) again 61-1/4 inches. So for those of you that didn't know I thought this info. might come in handy if you are wondering what rear end/ tire wheel combo you might want to put in your 70-72 GS, GSX, or Skylark! Thanks, Eric PS ...Still looking for a 3.23 ring and Pinion and a posi carrier for the 70 8.2 for $100.00 to $150.00
You think 3.64 is too much huh? Mine is 3.91, thats not all fun when driving the country I tell you Seriously thinking about changing! Just dont know to what.. And. Is it common to have less clearance(tire to body) on one side of the car than on the other?
You should do what I did and put in a built 200-4R. I get to keep my 3.73's and have steeper gearing to get me off the line to boot. :3gears: Cruising down the highway just went from 3200 rpm's at 70 mph to 2200 rpm's. Ahhhhhhhh.
I run 4.10's on the street and have no problem with cruising the interstate. I run a 30" tall tire though, which helps.
Yes.....There was "Wiggle Room" designed into the Body / Chasis alignment when the two were mated at the factory. My car is off by almost 1/2".... Harold Rolls has the information locked in his brain on how to correct this....perhaps he will detail it for us. It involves un-doing most of the body mounts
I had a choice of 3.31:1 or 3.91:1 when I did mine over Very happy I chose the 3.31:1. Seems a very nice compromise gear. I can do 75 on the highway all day long with no worry
Current choices for anything 12-bolt and NEW (from any R&P manuf.) go from 3.08 and jump to 3.42 with nothing inbetween
Really? This rear end was done about 5 years ago. The gentleman selling them had several to choose from, but only two 12 bolts were done- the 3.31:1 and the 3.91:1. They were all freshly rebuilt by a shop, don't remember which one. He had a deal going with them if I recall- the shop owner could store his cars at the man's storage facility in exchange for good prices on the rebuilt rear ends and trannys the guy had, mainly for '68 to 72 Chevy A-bodies. (His main biz was climate controled storage, the guy's 9 year old son let me sit in President Eisenhower's limo :TU:That kid knew so much about old cars it was like I was involved in a practical joke) 3.42:1 should be a nice gear, too, but his 10 bolts were all 2.92:1 and lower, and I had just wiped out a 2.56:1 and wasn't interested. I was tempted to get the 3.91:1, but a rare burst of common sense made me get the other one. I would have picked up the 10 bolt 3.42:1 in a heartbeat but I can't say the 12 bolt has been a dissapointment
Yes....for several years now (I did mine about 3 years ago) and for a 12-bolt the only thing then AND now (I've checked recently) is 3.08 and jumps to 3.42. I would have gone with 3.23 myself if I had the choice
I was just told that the new 8 1/5 chevy truck rear ends would be a good choice if I ever decided to swap out my 9 3/8 Riviera rear end (for better gear options) Even comes with disc brakes. What are the veiws on this?
