James G. Posted March 10, 2012 Share Posted March 10, 2012 Hey guys, I am looking to swap in a posi rear end into my 1972 Monte Carlo. I currently have a 10 bolt open rear end with 2.56 gears (original rear end, ID #L K B 1 5 2 2). I have a guy who would be willing to sell me a rear end from a 1969 Pontiac LeMans which is a posi unit, 10 bolt. My questions are: 1) Would I be able to bolt the 1969 LeMans posi rear end up to my 1972 Monte Carlo without much modification? 2) If it would bolt up pretty easily, would it be worth the $400 price tag since the unit appears to be in very good shape, gears look good and no rust on it at all? Any help would be greatly appreciated, thanks! -James Quote Link to comment Share on other sites More sharing options...
714024SPEED Posted March 10, 2012 Share Posted March 10, 2012 Yes James the rear end will bolt in with no problem.You may need to change you ujoint on your drive shaft.I put a 12 bolt from a 70 MC into my 69 Lemans convert.with no problem i needed to change the ujoint. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted March 10, 2012 Share Posted March 10, 2012 I agree, the u-joint should be the only issue Quote Link to comment Share on other sites More sharing options...
MGD72Monte Posted March 11, 2012 Share Posted March 11, 2012 2.56 gears!!! I thought 2.73 were the lowest gears available in the Monte. Was that a special high mileage or top speed option? Quote Link to comment Share on other sites More sharing options...
Big Jim Posted March 11, 2012 Share Posted March 11, 2012 That's what I've been told. I changed mine to 3.08 limited slip. Quote Link to comment Share on other sites More sharing options...
Montemedic Posted March 11, 2012 Share Posted March 11, 2012 My 70 SS came with a 2.56 12 bolt posi in it. It's also on the build sheet. Quote Link to comment Share on other sites More sharing options...
MGD72Monte Posted March 11, 2012 Share Posted March 11, 2012 My 70 SS came with a 2.56 12 bolt posi in it. It's also on the build sheet. Must be on big block cars only then. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted March 11, 2012 Share Posted March 11, 2012 2.56 were stock gears in 1970 for the SS454 Quote Link to comment Share on other sites More sharing options...
James G. Posted March 15, 2012 Author Share Posted March 15, 2012 Ok, so it seems the u-joint would be the only issue. What kind of u-joint would I need for this swap to work? Sorry for all the questions, but I have never swapped rear ends before, so this is new to me. Thanks! Quote Link to comment Share on other sites More sharing options...
speedfreak71 Posted March 17, 2012 Share Posted March 17, 2012 Seems a little high priced for a 10 bolt. There are plenty of chevelle and monte 12 bolts still around. They are stronger and help the value of the car. The last 2 I've bought for $250 a piece. I found a aftermarket posi on the net for $235 shipped and found some used 3.31 gears for $50 and have been very happy with it. And the 12 bolt just looks MEAN Just my 2 cents worth Quote Link to comment Share on other sites More sharing options...
714024SPEED Posted March 25, 2012 Share Posted March 25, 2012 You have to look at your u-joint it might bolt right in.I had to get what is called a "trick joint" it has the small caps on one side and the large caps on the other.I got it at my local NAPA auto parts.Also look to see if your joint has inner or outer clips,or if it is org.to the car it may still have the nylon in it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.