I haven't been to the truck yet to get that chassis number, but I will. The 2 speed diff is getting repaired so it'll run in high gear.
I spoke to previous owner who had the truck from 2003 until 2015, he said 235 was the engine the truck had when he got it. He was told the truck had the original engine in it when he bought it (which of course may or may not be the case).
And I still find pretty much every parts supplier for the 1961 C60 is showing a 235 engine option. Considering that, and the fact that it's unlikely someone would have replaced a 261 with a 235 (rather than a V8 or another 261) it's looking like some of the C60's in 1961 must have come out with the little 235.
Checking Autozone's info, they show the 235 as an option in the C60 through 1963. And as mentioned, Advance, O'Reilly's and a source online called US Autoparts all show the 235 at the top of the pick list for the 1961 C60. So... it's strange that GM showed only 2 engine options for that truck in 1961.
I'll update with other info as I learn more.
Dan
