Thanks guys! I found some of the tech info on variuos web pages and went home last night to check things out. You might like this story! I had the numbers to check and their location on the engine but when I looked in the spot the block casting was supposed to be, there was nothing there. Just flat smooth clean paint (I had washed the engine over the weekend). It was smoother than the surrounding painted metal in fact. After taking a wire brush to it, off came the paint, then a thick layer of oil and grime that was concealing the number! A previous owner hadn't properly cleaned the beast before painting it!
It is indeed a 261 and the one in the truck is a 235. Now I can put my fears to rest and start stokin the new stove1
cheers, and thanks,
Ryan
