[DADZZ64]

hey guys i have been trying to figure out stuff about my rear end i want to make it some what posi and was thinking about putting a spool in it i was looking at summit racing and see a few options but i dont know what size i need to use : Spool, Mini, 26-Spline, 10-Bolt, GM 7 1/2 inch or Spool, Mini, 28-Spline, 10-Bolt, GM 8 1/2 innch iam very new to the rear end stuff and need help is the rear end a 10 bolt or 12 and what size spool will fit .. if this is a dumb question sorry but i gotta find out some how ..and also what rear ends will fit a 64 bonne???

[64catdroptop]

dadzz64,

I had to replace my ring and pinion a year or so ago. They don't make gears for the 61-64 Pontiacs (full size) at this point. The problem is that the bolts used for the Pontiac ring gear are a 5/8" and the other GM (chevy) use a 1/2" bolt. I bought a set of used 3:23's to replace my chewed 3:23's.. I love the ratio, gets me outta the hole quick, burns about a 12 - 14' patch starting at 10mph, but still drive nice on the road.

But like Pitt64 said, unless you're racing, stay with the higher gear ratio, if you get too tall on the ratio - like a 4:11, you're probably gonna hate it for a driver.

-r-

[DADZZ64]

thanks guys ... i got a turbo 400 in the 64 bonne the site pitts linked me to has a set of 3.42 s that look good to me but iam wondering if i can get those gears from summit .... what size would the ring gear be ??

[DADZZ64]

HMMMM what about these gears ??? http://store.summitracing.com/defaul...5&autoview=sku

[Jon Wood]

Can't get the gears from summit. The gears you linked to will not fit, these are for the later GM differentials. The only place I know of to get gears and good rebuilt differentials for the early ('59-'64) BOP fullsize cars is fabcraft metal works.

[DADZZ64]

thanks for the help guys this forum is the best if you guys happen to come across a used set of 323 or 342s for sale please let me know

[64catdroptop]

One thing you need to be aware of is that the carrier for the 3:23 is smaller than the 3:42 (that's the "break-off point"). There are 2 different carriers for those rear end gears. The ring gear is larger for 3:42 and lower gears, while the samller carrier will accomidate 2:69 to 3:23.

-r-

[tom s]

3.42s can be put on a 3.08 carrier with a ring gear spacer.NBD.Also the 3.42,3.64 and 3.90 gears Fabcraft had made were made for the highgear(3 series) posi unit.You can still buy 4.10 and 4.56 gears from Summit.Tom

[Ron Landis]

I know of a complete 3.42 posi. I'll see if it is still available. I bought it for my '63 Prix when I was contemplating a four speed change-over. Guy I sold the car to may still have rear axle, as I included it with the car. Let me know. Ron. BTW...It came out of a '64 G/P.

[tom s]

I have a 3.23 and a 3.42 posi if you get stuck.Tom