I had a new 1970 SS 454 that was built in March 1970 at Kansas City (Leeds) and it came new with Goodyears.
L8DS 5 - The L8DS is the broadcast code and 5 means 5 each of L8DS. The tires would have been marked with L8DS and that would relate to the option package part of the Z15 or Z25 parts list used by plant operations.
PL4 F70X14WH LTR
PL4 - Plys of tire = 4
WH - White
LTR - Letter
RWL = Raised White Line
Here's a photo:
