1963 Split window proving ground car

[Duke W.]

Re: 1963 Split window proving ground car

In 1963 the HD brakes and suspension were only part of the Z-06 package, which also included Fuel Injection,. HD brakes are easy to ID because the brake drums have fins. The J-65 drums appear the same as base drums other than the subtle differences I mentioned in a previous post. Did you check for those features and the casting numbers. Photos would help.

Both the round and square section wire was used for the anti-squeak springs, and I believe there is some controversy over whether the anti-squeak springs were only on the front only or both the front and rear.

The front HD spring is identified by having thicker wire and possibly a different coil count. Details should be in the '83 Corvette "vehicle information package" that you can download from the GM heritage site.

I believe the rear HD spring was available from service parts long after the unique-to-'63 base nine-leaf base spring was exhausted, and this is probably why it is not uncommon to see a seven leaf HD spring on '63s.

Duke

[Thomas D.]

Re: 1963 Split window proving ground car

Duke
I was able to pull a number from the drum with the flat spring. The best I can make out is: 3878671. Is this the part # for the metalic brakes?

[William C.]

Re: 1963 Split window proving ground car

That would be a casting number, part numbers for '63 w/metallic linings are 3830168 front, (possibly 383067), 3821145, rear (possibly 3828687). At leas per the '63 Parts book.

[Duke W.]

Re: 1963 Split window proving ground car

...671 is likely an original drum, but, correct me if I'm wrong, both base and J-65 used the same casting, however, the J-65 drum was cast with a thicker web and these drums were identified with a stamped "X".

The OP needs to measure front drum web thickness. That will likely tell whether his car was originally equipped with J-65.

Removing the drum to observe the shoes will tell whether they are the original shoes.

J-65s can last well over 100K miles in normal road use. I have advised others with J-65 that have lots of shoe material left to just disassemble and clean everything, rebuild or replace the wheel cylinders, master cylinder and hoses, thoroughly flush and dry all the brake pipes and reassemble everything with DOT 5 or DOT 4 fluid. Use of DOT 5 should result in less long run internal corrosion due to moisture absorption, and nearly eliminates the need to do periodic fluid flushes to purge moisture that is absorbed by DOT 3 and 4 fluids.

Duke

[John D.]

Re: 1963 Split window proving ground car

Just for clarification. GM sells company cars to this day as new as they were never registered and still retain their manufacurers statement of origin (MSO). The discount offered to employees who purchase or "tag" these units is dependant on the mileage. If they are not tagged they go to a GM dealer only auction and they are later marketed to customers as demo units.

[Steve W.]

Re: 1963 Split window proving ground car

Generally "brass hat" (executive) cars were driven 3000 miles and then turned over. Engineering cars could see many more miles and were kept for a longer period of time. Then an assessment was made as to what modifications had been made and the cars were either returned to original state and sold in a dealer auction or scrapped. Another possibility would have been a "class A" purchase by an employe (bought essentially for the Wholesale price) and then turned over at the end of the model year, I know several folks that used to pick up a car each year and drive it already having a buyer in place when the new models came out. Lots of possibilities, but like Duke, I have a problem with a vehicle sold as "New" with high mileage. At least to my knowledge that was not a GM practice in the early 60's. John H may comment also.

My 68 was used by the Warren Tech Center (ZL1 Stripe Mule), sold to an employee with about 10,000 miles on it. The NCRS Historical Docs were great as they were another point of verification the car was shipped directly to the Tech Center from the Factory. (I highly recommend getting these docs...)