Posi

[Sam D.]

For a 1964 a corvette with a build date of 2/27/64, what would be a range of the posi casting date. Also what is the posi casting number for this car with a L84 engine? And what posi typically went with the L84? Is it 3.70 or 4.11

Thanks,

Sam

[Harry S.]

Re: Posi

Sam, if you have Noland's book, look at page 249. There is a chart with VIN numbers and rear axle codes. This will help you figure it out.

Harry

[Bob R.]

Re: Posi

You can use Harry suggestion to decipher the code. I attached a couple of photos of my May 63 car. The casting date is located directly above the rear spring on the drivers side. Very hard to see while the spring is in. The specific information on your car is stamped between the strut assembly and the spring assemble. My car is CJ 5 2 63. 308 ratio May 2 63 and the casting date is 12-24-62.

[Wayne M.]

Re: Posi

For a 1964 a corvette with a build date of 2/27/64, what would be a range of the posi casting date. Also what is the posi casting number for this car with a L84 engine? And what posi typically went with the L84? Is it 3.70 or 4.11

Thanks,

Sam

Sam -- sounds like your car is probably in the 12200 VIN range for a 27th Feb build. Here's a 4.56 diff I have off an unknown '64 VIN, but is probably only 2 or 3 weeks earlier than the diff. that would be found on your car.

Carrier 3818753-N; cast date J_18_3 (Oct 18th -- quite a spread from assembly); stamped on bottom: CF_1_3_64;

Also, trailing arm spindle supports dated A_6_4 and L_7_3.

I would say that 4.11 ratio gears would be typically (statistically) ordered with L76 and L84 engines (Noland's book shows 4.11's are almost double the 3.70's). But from the dealer driveline charts, with 4-speed, if you didn't specify posi (G81) your fuelie would have been built with 3.70 non-posi gears [CX code]. And if you were really cheap, you could get the base 3-spd transmission with 3.36 (non-posi ?) diff, even with fuel injection !