Cool old truck. It reminds me of mine when I first got it. I'm putting it back together now. It's only been nine years. I hope your faster than me. Technically mine is a 41, 1-1/2 ton but numerous modifications have been made along the way combining no less than seven trucks. Reminds me of Johnny Cash's Cadillac. Your discussion on engines caught my eye. I would think the simplest way to tell if you have a 235 verses a 216 would be the side cover. That would tell you at first glance what you would need to know. The 261 from what I've been told, has to have an oil filter, because the oil is forced into the filter. The filter case on a 261 is also about half again as big. The 261 was in a 58 but it was a 61 engine. I found 53 235 in a 46 grain truck it fooled me at first because I opened the hood on the driver's side. It had the old style valve cover with two bolts. The other side revealed the lifter cover of the new engine. When I took the valve cover off the cool thing was that the head didn't have the 4 holes it was a "modern" engine with the old valve cover. I ran the casting numbers, turns out it was made in Sept. of 53. I guess that makes it one of the first pressurized 235's. Maybe they just needed to use up some extra valve covers. The only sure way is to run the numbers. Best of luck, Hold on to the joy. The road ahead is long, and like the guy on the other end of the phone when I bought a $1000.00 worth of wheel bearings for a 2 ton dump truck. You love it don't ya! Yah I do.