I am getting an engine for free. It's a 396, supposedly 1968. It has been sitting outside for years and is pretty rusty. Has anyone dipped a complete engine in an electrolysis bath? Why can't it be done?

Heck, find someone with a lot of mercury and just dip it in that.

if it is rusty i would reccomend tearing it down and having it all checked then you can hot tank it and it will be all clean..plus since it has been sitting you want to know you have a good starting point

Buy the biggest plastic container you can find at WallyWorld and 3 or 4 gallons of muriatic acid from your local hardware store. Put the block in the container, fill half full of water, add the acid, then top it off. Leave it for a couple of days, it'll come out clean as a whistle. I had an old 454 that was the worst thing I'd ever seen, came out looking new. Only problem is where to dump the bathwater...

And before you dump the stuff, neutralize it with some limestone powder/chat or Arm&Hammer baking soda.

pdq67