The Stovebolt Site Forums The Shop Area Engine Shop Is the motor frozen, or just stuck? "it ran when I parked it there"

I don't know how underpowered it really is. That 261 (in good condition) is going to produce a lot of torque and should pull the truck and just about any conceivable load you could put on it.

That said, Jerry gave some very sound advice a few posts back when he recommended pulling the 261 (relatively scarce) and finding a running 235 donor engine. Probably still fine to do the "running flush" procedure with the diesel added. But given what you started with I'm still thinking it's running on borrowed time without a proper rebuild.

I'm very impressed at the perseverance you've shown in cleaning up the rusty mess and staying after it. Many folks would have given up at that point. This story is really a great one to follow.