It depends on several things, how many miles on the 366, how you want to use the truck if you swap motors, are either of the engines burning oil/smoking? The dieseling can be addressed and probably has nothing to do with the valve train. The 366 is a true truck engine, low RPM torque and heavy duty castings, the 454 is a good motor but not the same animal. The 366 probably has a Holley carb on it with an anti-diesel solenoid and a governor, I can't say if the 454 has a governor but probably a Q-jet carb, both carbs can be rebuilt if they have not been tuned with a hammer. Just a gut feeling here-I would keep the 366 in it.
Yeah, you did mention the anti-diesel solenoid and governor for the holly carb, I missed that, however, it was absent from the truck when I bought it and no wires or anything to suggested it was ever there. I took the carb off and went to Auto Zone and they sold me another Holly carb similar to the one that was on it at the time with no mention of a anti-diesel solenoid. I guess the Holly that was on the truck when I bought it was not the original, and when I took it in for a replacement, they gave me something similar. In their defense, they can't even look up my truck in their system as it doesn't exist. Too old I guess. It would seem you nailed it on the solenoid too.
But now I have an Edlebrock AVS2, so I'll start purchasing idle stop solenoids from Amazon until I find one that works. As you also suggested, I'll keep the 366 in it. She runs good.
Thanks for taking your time to help me out.
