It happens.
I can nolonger trust my memory so others can't either but,,,
First 67 fish was slant 6 904, 7&1/4 rear. Donor was Tradesman 200, 318, 727. Drive shaft from that donor was like 3 inch dia. I want to say I had it cut to 49&1/2 to fit.
6 or 7 years later the 727 came out, 904 went in. Back to the small tube driveshaft from a parts yard. Don't know that I ever measured it's length. Anyway,,, shortly after I found this website a owner needed a shaft for 904 to 8 &3/4 rear. I had the 49&1/2 length he needed laying here.