I searched around a bit but still need some inputs.....so here goes: At what point should you go from 28 spline axles to 30 spline axles in a full weight `72 Skylark with 3.42 gear? I assume when your 60' times go down to 1.6 or 1.5 range it is a good idea to upgrade the stock axles? I am interested in a list of components and cost for such an upgrade (oph or monzaz?). Thanks.
When I built my 8.5, I contacted Jim (Monzaz), and he gave me a purchase order number for 30 spline axles. When I called Moser, I had them reference that PO# and told them, "send me a pair of these" Cost me 357.00 with the shipping. I paid 495.00 for the Eaton 30 spline Posi, but I bet Jim can get you a better deal. I had a local shop build the rear for me, in all it cost about 1700.00. Again, Jim can do better I'm sure. Wish I knew about him before. I had my shop call Jim because they had a few questions that I couldn't answer. He helped me out a lot.
That's a lot of coin, specially for this time of the year.....just to get stronger axles. Maybe an intermediate plan will work?
I think 88/89 and up 8.5" axles are 30 spline. I pulled an early 90's Cop car/Imp SS rear apart and it had the 30 spline posi with 3.23 gears. They are heavy duty units and can still be found, especially in wrecked cop cars!
88-up GM use 30 spline axles. You should be fine with 28 spline axles and a good posi unit. Many members in the 11 sec range with a 8.5" rear and 28 spline axles. Monzaz can give you all the details. Email him direct.
I'm still using stock posi,and stock axles. This season i have 74 runs on it from 1.56 to 1.62 60ft. Last season with a different combo same rear 67 runs in the 1.7x range. This rear and axles had 112,000 miles on it before i put a used posi and used gears in it. Then i started beating the crap out of it.ou: Maybe I'm pushing my luck, but i'll keep going till I find its limits.
Dave, you are hooking better than I expect to....so maybe I'll be fine with only a driveshaft upgrade? What driveshaft are you running?
Well I can quote out anyone any build they want. I can provide you with parts or the whole rear Done bolt in ready even with a complete brake package...Remember my brake package is all the way to the rubber brake hose and hard lines on the axle housing DONE! You get it all. for 195.00 NEW on the brake package. A complete performance package for your buick 8.5 would break down like this >8.5 clutch type posi 399.00 (28 or 30 spline) >rebuild kit with everything but the axle bearings and seals 89.00 -includes pinion inner and outer bearings and races, left and right carrier bearings and races, pinion nut, crush sleeve, seal, 10 ring gear bolts, rear cover gasket, carrier and pinion shims, marking compound and application brush...that about covers that... prices always subject to change because of time frame that may go by or suppliers raising their prices. Jim >Moser custom 30 spline axles 319.00 >Timkin axle bearing A9 and seals 712146 69.00 for the pair >Heavy duty 3/8" think retaining plates 35.00 >ring and pinion 3.42, 3.73, 3.90 4.10, 4.56 all 139.00 USA Standard street gears and 169.00 performance Yukon Brand gears Shipping will depend on how much your buying and where it is going to. Moser axles will be a direct shippment as to save on extra shipping to me then on to you....Unless you want to pay extra for that silly idea...lol. Just PM me if you ever have a questions...always here to help. Jim Mitschke
When I swapped the 8.2 out of my 70GS455 to a 8.5 I bought a good used posi from Jim(monzaz). He will treat you right! Bert
$1700??? How'd you get that much wrapped up in a 8.5 rear. I've probaly got about $900 to $950 in mine.
Bob, by the time you add up a new 30 spline posi, new gears, and axles with a bearing kit, axle bearings and seals ect.... add tax and labour to build it...$1700 is about right.
