I just pulled the valve covers off my 4.3 to clean them out before I drop it into the buggy and they were NASTY. The motor ran great before, so I was wondering after i scoop out all the crap thats in there what should I use to clean off everything? I had some people tell me to get some Marvins Mystery Oil and put it in a spray bottle and spray down all the moving assemblies and some have said use carb cleaner. Just looking for some helpful info, thanks.

just do a full kerosene motor flush or an off the shelf flush. if the valve covers are that nasty the whole motor is.

Run some sea foam through it. It works awesome. Get it a auto zone.

Back in the day my dad used drain the oil and put ATF in. then he would crank the engine and let it idle for 5 to 10 minutes. After that just drain it and fill it back up w/ oil.

Frank

x2 sea foam works great. just remember, a lot of older motors run well because of all the carbon build up on them. its actually sealing the motor up. in some cases when you flush the motor and it removes this carbon buildup the motor may then burn oil, or even leak oil.

x3 Seafoam! Down the intake while running and in the oil.

Your better off just pulling the pan and valve covers and powerwashing everything before you install it, Don't forget to clean out the oil pump pick-up, you will regret it later if you don't!!!!!

When you reinstall the motor, be sure and prelube it for a few minutes to help push all the water out of the mains and cam bearings.

flushing always gives me the creeps. no telling what you'll loosen up in there. how about just doing more frequent oil and filter changes and some seafoam to slowly breakdown the junk?

use trans fluid like sea foam add a quirt and run till oil change

Added gunk is one of the side effects of going from conventional oil to a so called "detergent" synthetic oil. I've had that effect in my engines for years.
Sea foam it and do a flush. clean out the oil pick up screen too like someone else mentioned here. I've heard a lot of crap about the "marvel mystery oil" If it's a "mystery" I'd stay away from it - sort of like a "snake oil cure" in my opinion.

thanks guys, sounds like its goin to be the sea foam.