['ol Pinion head]

Originally Posted by FunctionalShaker

The assembly manual, dated 2/18/70 shows the 480033 and 480036 fans to be used optionally/interchangeably, though I've yet to see a 480036 fan.

Have yet to run across a 480036, either. The 48xxxx lineage part numbers & casting numbers were not introduced until mid summer of '69. The 480033 fan was released for use on '70 Performance V8 Firebirds & also was used on at least mid year '70 Pontiac V8 performance A-bodys & GP's. It was used up through the '72 models. The 5 blade flex fan again changed part numbers (& design) for '73, & went to wider spread between two blades. Have several in the '73 & early calender year '74 range.

The '67 to early '70 usage 5 blade flex fan was speaking of earlier is a 9791346 / "346" for short. Have several mid to late '68 dated versions. Have also pulled quite a few more off '69 models & 70 models & the trend I've noticed is they typically predate '69 Pontiac A-bodys by 4 to 10 months. From what I've examined on original cars, they have not been not tight dated like alternators.