HI guys, I've got this 71 Skylark with bolt in axle/8.5" with 2.56s. I want to rebuild this hole rear so it will handle my abuse for years to come. I'm torn on what Posi unit to go with. Any recomendations? I have a pair of 80 Z28 3 series carriers, should I just use one of these? Also should I upgrade the axles to 30 spline? Drive train mild 455 with ported heads/413 cam/sp1......200r4 trans Thanks in advance guys.
Blueprinted 8.5 "S" spring posi units have held up down into the mid 1.50 60 foot times in foot-braked 3800 lb A-bodys. Personally know several guys in DFW area that have 300-400 runs at the strip on slicks in the 11's with their "S" spring posi 8.5's. Have also ran across guys who have tore up the S spring carriers in slower 60 foot time cars which hit the tires real hard. Usually the ones destroyed were in leaf spring cars taking the hit of a 200-250 shot of nitrous, a few lengths out of the hole, at the strip on slicks... not smart. Can't really say your question was vague, but in answering, have no idea what your goals are with the Skylark or how strong the ported head 455 Buick will be, or how many upgrades the 200R4 has been given, so can only be conservative... If goal is limited to a mid to high 12 sec 3700-3900 lb Skylark, you should be oalright with correctly rebuilt 8.5 S spring posi unit & stock axles. Built tons of the '8.5 A-body rears over the years for similiar application with no problems. If, however, you're planning on stepping it up later, & not willing to spend $150-200 to have a low ratio "S" spring posi carrier rebuilt w/ new clutchs correctly shimmed up... its's time to put some $$$ in the rear. Can always get some bucks out of the used 3 series posi carrier. Wanting to go 30 spline route, there will be close to $825 expenditure on new 30 spline Eaton carrier & new 30 spline Mosers with new studs & new axle bearings & seals. Different carrier bearings will also have to be used, so no reason to purchase a full 8.5 bearing kit. Need more info, feel free & shoot me a PM. Got Posi? :3gears: Roger
Hi Nick, IF you are looking for bulletproof then look no farther than this: http://www.v8buick.com/showthread.php?t=106538 ....especially if you are wanting to go ahead and go with 30-spline axles anyway. No tearing this puppy up or wearing out clutches or springs. You'd NEVER have to worry about that part failing again!:TU:
