Last year 534 was offered?
 

I always thought it was 1978, but then I heard 1981?

FWIW, Wiki says '81. Can't find any other source on line right now.

Yeah, I thought I saw in the 1981 C-Series brochure that it still could be ordered with the 534. I wonder what it's last years horsepower&torque ratings were.(?)

Best I can find is post 10 here:

https://www.ford-trucks.com/forums/4...yone-else.html

The last year was 1981, and the 534 was offered in C/CT-900's and Louisville 900's. VERY few were built after 1977 or so, and most of the later ones ended up in fire apparatus or were industrial 'crate' engines. I don't have the H.P. and torque figures handy, but at the end the 534 was in the ballpark with the Lima 429. That was a big reason why it was dropped in 1981.