460 ford problems

Obviously just a guess here because its hard to tell without "being there", but I would suspect something in the valvetrain let go. As for what, it could be a multitude of things. First of all, don't drive it!

I would start out with a compression test. If you find a low cylinder then it is either a bent, broken or burnt valve. If the compression test shows good, then I would pull the valve covers and inspect the rocker arms, pushrods, valves (as much as you can see), and the valve springs. Normally I would do the visual inspection first because an engine making noise is best left not running. In the case of an RV it is probably easier to do the compression test than it is to pull the valve covers.

If neither one of these checks reveals anything, then post back here with what you do find. I would venture a guess here and say one of these two checks will reveal something.

Chris

If your motorhome has been sitting long enough, the gas has gone bad and you've just varnished your valves to the heads.

I made that mistake. Stuck valves and bent pushrods. I now have a 390 that needs to be rebuilt. I've learned, the hard way. Before starting a vehicle that been sitting a long time, check the gas, if neccessary drain the tank and carb, disconnect and flush the fuel line and replace the fuel filter.

I'll find out if I bent any valves when I pull the heads.

BigDave