I JUST FINISHED A 30 OVER 455 WITH TA HEADS AND INtake poston cam which recomends 3.90 gears the car is already so crazy Iam afraid i am going to brek the original rear end anyone have any info on which 12 bolt gm rear ends will work without to many mods this is a #s matching car and i would hate to ruin it (camero chevelle) any info would help alot thanks glen
Glen, with the proper set up the 8.5 will take the beating. The question is will the original driveshaft and u-joints? ,but thats a whole nother question in itself. My personal opinion is 12 bolts are overrated compared to the 8.5 10 bolt. You've got lots of options to beef up either one. (68-72) for the 12 bolts and (71-72) Buick Skylark for those lovely bolt-in axles. You can buy a rear end cover girdle even aftermarket axles for some added strength. Good luck with your choices and ask lots of questions :TU: ...Tim
Glen: The 68-72 12 bolt is a bolt in item. Reasonably easy to find and many aftermarket parts (carriers, gears, axles, etc...) I put one in Jim Dillons 70 Stage 1 conv. 4-spd. as he'll be pushing some good hp numbers through his alum. head engine also. TA cover is a nice addition. Its not that the original 8.5 can't take the abuse, its just hard to replace an original item if it ever gets broke. I'm about 70 miles North of you. You going to BOP on Oct. 1? Dave
Glen, Guess I'll sound off, have built more than a few for similiar vehicles. Unless you can swing a new 2K+ Moser 12 bolt A-body rear (comes with bolt-in axles), OR want to spend $1750 + on an all fresh strengthened 12 bolt Chevelle rear with new HD posi, local installed tapered bearing ends, & tapered bearing bolt-in axles... building an 8.5 A-body rear is the way to go. Can have one built off your original hsg... or off a core hsg (prob smarter choice). Pricewise, an extremely tough 8.5 A-body rear can be built for around $1350, choice of 3.73's or 3.42's, new Eaton 30 spline carrier, & new bolt-in tapered bearing Moser axles & 1/2 studs. A good option is to have the rear built with LH billet cap or use a T/A Performance cover, lh cap movement can thus be stabized. What are your plans for the car? Note its a 4spd car... Heavy GS with 4spd, heavily dragraced with big slicks & linelock??? If so, the M22 will be weak link before propperly built 8.5 or 12bolt. Just my .02. :3gears: Roger
