- Joined
- Mar 10, 2011
- Messages
- 5,960
- Reaction score
- 112
- Location
- Oklahoma
- My Car
- 1971 Boss 351
1971 Mustang Sportsroof
1972 Q Code 4-speed conv.
For everyone trying to restore their cars to as close to original as possible - here is a real observation of the casting date on my Boss 351's original block.
1F173943 is a square block with a casting date of 0L25 Nov 25 1970
1F02R173943 was produced Feb 12 1971 and was 3 days ahead of schedule
This indicates my car's block was produced very early in the production cycle for all Boss 351's. But not pulled from inventory and utilized until about 78 days later! So for me - casting dates on parts just need to be prior to the actual build date and within a couple of months. Only exception would be if you are dealing with a part that was changed prior to your build date. This would limit your time for acceptable date codes.
Ray
1F173943 is a square block with a casting date of 0L25 Nov 25 1970
1F02R173943 was produced Feb 12 1971 and was 3 days ahead of schedule
This indicates my car's block was produced very early in the production cycle for all Boss 351's. But not pulled from inventory and utilized until about 78 days later! So for me - casting dates on parts just need to be prior to the actual build date and within a couple of months. Only exception would be if you are dealing with a part that was changed prior to your build date. This would limit your time for acceptable date codes.
Ray