Mine was a '73, the last year of the 1 piece fiberglass roof, I think. I saw it on a dealer's repair lot. It had a 327 and a 3 on the tree, the only one I've ever seen on a Blazer. The linkage was worn out and they couldn't get the parts to fix it. I found a floor shift conversion kit that I knew would fit and make them an absurdly low offer. They grabbed it. It had about 100k on it. It took me 2 hrs to install the shift kit and I ran it another 100k. Then I sold it for the same price that I'd paid for it years before. I had a ball with that thing. It seriously needed a 4 speed but by using the low range to get moving sometimes, it never failed to get me there.
75 was the last year of the full top Blazer. Someone must've swapped in a 327, if that's truly what was in your Blazer. IIRC, 1969 was the last year for the 327.
