I have no idea who built the engine, it was done before I bought the truck. I know it doesn't burn or use oil, so there's that. What I've done to it has made it better by a long stretch. The thing that gets me is my basically stock 350 in my '81 has no issue with smooth power up to very high revs. It has no tachometer, and is running 4.10/4.11's, I forgot which ratio, and will do the 85 mph shown on the speedometer without missing a beat.
But the engine in the '65 seems to struggle, and doesn't seem as smooth by any means. Have never had a 350 act like this one. Again, it's reliable, just seems to struggle in certain situations. I understand there is more insulation in the '81 so it is much quieter in the cab as compared to the '65, but engine sounds in the cab or lack thereof has nothing to do performance.
To me, the flatter the torque curve the better, granted it is higher torque number. That should equate to an engine that doesn't struggle to get things moving or keep them moving. Unless I am missing something here.
