'64 Power Brake Booster Models & Julian Date

[Fred M.]

I have an original '64 power brake booster, model# 4311. What I don't know is how to interpret the julian date, 163. Would that be the 163rd day of 1963 or 1964? I also know model# 4310 is a correct '64 PB booster. Can anyone offer me any insight as to why 2 models and how to properly interpret the julian dates on each model. Thanks

[Cliff K.]

Re: '64 Power Brake Booster Models & Julian Date

Fred:
As far as I know, the year is not stamped, only the Julian date. You can get a Julian Day Table with an internet search.

1964 was a leap year (there is a Julian table for leap and non-leap years), 163 would be June 11.

1963 Booster is 2025 or 2110 whereas 1964 is 4310 (4311) or 4702. The build date of your car should give you the clue to which year would expect the booster to be made in. Let us know what you find.
Cliff Kennedy

[Fred M.]

Re: '64 Power Brake Booster Models & Julian Date

Cliff, Thanks for the reply, all good input and you are correct that these PB Boosters did not have a year date, only julian date. Therefore, I'm left wondering if this particular PB Booster would be chronologically correct for an early '64 or late '64. In June of '63 GM was obviously producing parts for the '64 line of Corvettes just like they would have been doing in June '64 for the existing line. How would an NCRS judge view this particular PB Booster on my '64 which was produced on 19 Nov '63?

[Bill B.]

Re: '64 Power Brake Booster Models & Julian Date

I also have a '64 with an 11/19/63 build date(C19). FYI, my brake booster is #4311 and the Julien date is 296 (10/23/and I assume 63). I believe the booster is original to the car. By the way ,my serial # is 105354, what is yours?

[Cliff K.]

Re: '64 Power Brake Booster Models & Julian Date

Fred:

The assumption for your car would be that the PB booster is a 1963 build. 63 was a non-leap year and the Julian day would be June 12, 1963.

Typically, we see components dated within a few weeks of the car build date, but, obviously not always. For this reason NCRS allows dates within 6 months of the car build date. So, for your booster it would be 5 months and 1 week, within the 6 month allowance. Even though the date is reaching close to the outer limits, in my opinion, the date should be a non-issue.

Cliff

[Fred M.]

Re: '64 Power Brake Booster Models & Julian Date

Cliff, great. Really apprciate the insight, very helpful.

[Fred M.]

Re: '64 Power Brake Booster Models & Julian Date

VIN is 05348. Very close.

[Michael H.]

Re: '64 Power Brake Booster Models & Julian Date

I have an original '64 power brake booster, model# 4311. What I don't know is how to interpret the julian date, 163. Would that be the 163rd day of 1963 or 1964? I also know model# 4310 is a correct '64 PB booster. Can anyone offer me any insight as to why 2 models and how to properly interpret the julian dates on each model. Thanks

Fred,

The only correct power brake booster tab number for 64 is 4311.

[Michael H.]

Re: '64 Power Brake Booster Models & Julian Date

1963 Booster is 2025 or 2110 whereas 1964 is 4310 (4311) or 4702. The build date of your car should give you the clue to which year would expect the booster to be made in. Let us know what you find.
Cliff Kennedy

Cliff,

The booster tab number for all 63's, including Z06, is #2574. I'm curious as to where you found the 2025 and 2110 numbers.


Also, as mentioned above, the 64 booster tab number is #4311. No record of the #4702 exists for Corvette that I can find.

[Cliff K.]

Re: '64 Power Brake Booster Models & Julian Date

Michael;

I got the numbers from the NCRS 63-64 Judging Guide, Fifth Edition, pages 122 & 123.

Cliff

[Michael H.]

Re: '64 Power Brake Booster Models & Julian Date

The information below, directly from Delco, shows the correct "tab number" for the boosters used for 63 and 64-65 Corvette.

I don't know where some of the numbers came from that have been floating around in the last few years but I have to guess that some folks were making Corvette boosters using shells from other passenger cars and installing new rear brackets for Corvette.

I've never seen any tab numbers on unrestored cars other than the numbers shown on the sheets below.

Note that for 64, the tab number is 4311, one digit higher than the "assembly number". The assembly number, #4310, is a booster and master cyl assembly. That's why we know the 4310 number was never used as a tab number for the booster.

[Doug F.]

Re: '64 Power Brake Booster Models & Julian Date

my original 17000 # 64 has the 4311 with a date code of 104