i have a local guy here selling a differential off a 67 chevelle i think, there is a possibility of the diff being an 8.2 but he has a seperate posi unit with the following ring gear numbers 398483 12 41 57 i know it is a 3.42 gear, but want to see if its a 8.5 and not an 8.2..
so i went and took a look at the posi third member and here are the casting numbers on the posi.. they are 410408n..is this an 8.5 or 8.2
8.5 10 bolt c-clip posi unit BUT can be used in either bolt in or c-clip rear 28 sppline axles with and ratio from 2.73 to 5.57 ratios and everything in between. Jim
Great...Just picked it up for 50 bucks. what a deal huh.. looks to be good shape, was dirty but good shape, although mine does not have that z looking part in the middle..will i need it, also the other downside is it has a 3.42 gear but no pinion..would i be able to look for it seperately..
Get the S-spring....it is a pre-load spring for the clutches....Monzaz should have them. No pinion...then discard the ring gear...those (ring and pinion) are made as a set and do not interchange.
Thanks guys..thats good help. i will try to contact monzanz and see if he can sell me one..thanks so is this posi good compared to others, anyone know what year this is off of d23
another question, a while back i removed a thirdmember from a 2001 chevy 1500..this is a 10 bolt 8.6 rear end i think.. i have the entire thirdmember with a good set 3.73s will these fit my 8.5..just curious.
thanks gsstage1...always glad to hear from ya.. :TU: thanks to all...time to install and then tear up the streets:3gears:
So i just checked out my teambuick.com board post there and Jim, Monzaz replied and said that all 70-2008 8.5 8.6 corporate axles are the same, and said i could definitely use the 3.73s with my differential..now for the big question will the 3.73s work great with my setup... 73 455 71-72 455 heads with stage 1 valves headers b4b intake 830 cfm carb, th400 tranny i will bolt these gears up to a 410408n posi unit.. slowly getting rid of all my problems..cant wait till i see how the car runs..
so what about the 3.42s i do plan on using the car on the highway but not all the time, maybe once or twice every other week..i mainly want it to launch hard, forgot to mention i have a 2400 stall converter on it..
Still go with 3.08....will launch hard enough with the converter you have.....you main concern will be traction.
That sounds good, i have a 30 spline posi that came with 3.08 gears i think..i know i can find allot of those in the junkyard, so with the 3.42s you think i will be spining the tires for too long..so the higher it is say 3.73s the more spin the wheels have right, but the harder you have to push the engine to go faster.
Yes, too much gear will not be good for your mileage or wallet. The newer truck posi units are gov-locks...and are not worth anything since they have a strong tendency to come apart...1988-up are 30 spline posi units.
