Hello i found a "sledged" car in a JY. It was a 305 5speed with rear discs. What gears would be in the rear end? no rpos so thats no help. I might be switching from my aluminum drums to these discs. Any thoughts?

 

Not enough information however according to the TGO database;

A 1983 with a 305 and manual transmission usually has 3.23 gears. If it has a G92 RPO code or the car is a Z28 with a 4bbl HO engine, it will have 3.73 gears. Without an RPO list, the only way to know for sure is to pull the cover and look inside.

 

Thanks alot Stephen. Im pretty sure the car was a z28, it had a fiberglass hood. Ill go there and pull the cover off to count teeth. Im hopeing its the 3:23, I have 3:08 gears now, so hopefully the 3:23s would give it a little more push. 3:73s might be a bit much for highway use. What is your opinion on the 373s for highway? Ill do a search

OK it looks like the 373s will make me run 18% higher rpms, while the 323s will be only a 5% increase in rpms. Hmmm maybe some 3.45s or something. 373s are out of the question as i do mostly highway cruiseing, but want a little more around town.

 

Check to see if the vin is "G," which would make it an L69 (305HO) and, probably, a 3.73 car. A vin "H" car would probably be 3.23. As Steven mentions, however, only pulling the cover will provide the truth.

JamesC

 

Thanks James, the only problem is there is no car, they crushed it. But they saved the rear out of it. I can get a disc disc proportioning valve from another car though. The only way i know what the car looked like was this. https://www.thirdgen.org/forums/hist...tory-some.html yea its the same car. I know its locked Scottmoyer but i just want to show it to get help on this subject.

 

Under the circumstance, the above is your best best.

41 : 15 = 2.73
41 : 14 = 2.93
40 : 13 = 3.08
42 : 13 = 3.23
41 : 12 = 3.42
41 : 11 = 3.73

JamesC

 

There should also be an axle code. Stamped on the front of the passenger side tube close to the center of the diff will be a code. It's normally difficult to find and read because of dirt, rust and light stamping. That will tell you what was originally inside the diff.

 

Thanks for all the info guys, When i get that plate off ill know for sure.

 

I ordered my car with 3.73 gears, no posi. I had the original .94 (I think thats right) overdrive T-5 and 215/65s so on the highway it ran really nice. About 2200,2300 at normal speed limits. Lots of snap off the start and good highway runout. I later installed a WC T-5 with deeper OD and similiar 1,2,3,4 gears, which netted a loafing 1900 at 55mph. Stock it got 21 mpg combined driving average.

 

If it's an '83, you won't find a "G" VIN. It'll be a "7" VIN if it's an HO L69 car. I'm guessing it's not since it has disc brakes though. The vast majority of the HO cars in '83 came with one-legger 3.73's with aluminum drums...(first year of the L69 option)