ok its been a long time since i've had money to work on the buick...i'm looking at changing out my 2.56 open diff with something else but i can't afford to buy all new stuff for my rear end...i have a 12bolt chevy with 4.10 gears but i can't remember what i did with the posi unit... i found a 2003 S-10 rear axle brand new from drum to drum...it has 3.42 gears... is there any way to make this work in the 72 buick skylark? thanks daniel duncan
With a 2.56 gear in the rear, I'm assuming you have a '71 or 72 Skylark. 2.56 & 2.73's were very common ratio for 71 & 72's. S10 rears were all leafspring, not coilsprng, & the S10's are too narrow to bolt into stockwheel house A-body, even if one went to the trouble to rig up some form of ladder bars. Vast majority of S10 rears were 7.5/7.625 design. Being relatively weak, I've never ran across anyone who's gone ladder bars w/ a 7.5 r/e. The S10 rear may be an 8.5 if it was from a 4 wheel drive. Am not up on latemodel S10 internals as much as earlier versions. Bought cheap enough, that might be a set of gears for you, but be forewarned, every S10 rear I've ever ran across that was factory posi, was a gov-lock... very weak design & they do like to grenade. Assuming your ride is a '71 or 72 Skylark, I'd sell the 12 bolt housing & the 4.10's, then build the original bolt-in axle 8.5 10 bolt. Until one spends the $$$$ converting a 12 bolt Chevy r/e over to aftermarket bolt-in axles with a 33 spline HD Eaton posi, one really doesnt have an edge on a well built aftermarket axle 30 spline 8.5 r/e. :3gears: Roger
thanks for the info...i guess i was just really hoping as it was 175 bucks... but yes my ride is a 72 skylark...though i have a 73 electra motor 455 in it... alright...i think i have some people who might want to buy the 12bolt off of me... thanks
Daniel Go cheap and get a posi out of the local junkyard and keep your 2:56s When I took my gears out and put the stock rear back I picked up 2.5 MPG dropped my rpm at 55 MPH from 2450 RPMs to 1800 RPMs. All it cost me was .04 of a second ET and that grunt feel that gears give you. o No: Dave B
i've thought about that...wheres a good list of what rear ends came in what buicks? also i don't know but i have a parts 64 special deluxe...though i doubt its a posi... what cars had posi that i can look for? most of the junk yards in my area have 80+ ...there is a yard that has a 72 buick skylark custom...some of them had posi didn't they? i am getting a 200-4r very soon thats all rebuilt...so i was almost wondering if my rpm's will drop too much with such a 2.56 gear... thanks for the responses thus far
Go here http://www.buickperformance.com/posi.htm It will tell you what cars to look at to find 8.5 rear with posi, I'm assuming that is what your looking for. If you have an 8.2 rear you will have problems finding anything for that. The S 10 rear will work if it's 8.5 corperate unit but your axles wouldn't work because somewhere around 1988 they changed the number of splines on the axles. Yes if your going overdrive then you should go at least 3.42 gears. Dave B
how do i find out if i have an 8.5 or an 8.2 rear? i used to have a page saved a few years ago that had all the differences...but i can't find it now. also i've heard the gears will work from an 75-85 or so suburban? is this right? and did they have lsd/posi? thanks
Try this link. http://www.buickperformance.com/85rear.htm Has pics to help you tell what you have, after reading that link click "home" there is a lot of interesting info on the Buick Performance Club site. Dave B
awesome. i saw that page last night when i was looking around but didn't click the link! thanks for the help dave! i finally have some money to help me fix the rest of my buick up so just trying to get everything laid out. thanks again
