I want to use electrolysis on my block and head. Are there any aluminum parts or aluminum plugs to be worried about or is electrolysis generally safe on a slant 6?

Not something I've seen asked before pertaining to an engine.
I see it asked in the tractor forums, usually in rust removal from fenders and such. But you should be safe in doing so if you so desired... On any "plugs" all I can think of would be something like freeze plugs which are usually steel but could be brass/ in any case especially since I'm guessing you're wanting to do this to clean internal water passages and such, I'd want to pop those out anyway so that the solution could get into every nook and cranny.
You must have a big tank to be able to dunk a head and block....

Ummm.....electrolysis is a line-of-sight procedure. If you want to get into the little passages, you'd have to run wires into/through them, with the wires hooked into your anode grid. Otherwise, the only surface to get cleaned would be the exterior.

Roger

Interesting. Didn't know that. I thought as long as the tub, drum, etc was big enough to completely submerge parts in the solution within, that it would clean everything within.

Nope. Just like chrome plating, but in reverse. There has to be an unobstructed path between cathode and anode. Chrome plating is just chromium dissolved into a solution, and the act of passing current through it carries the metals with it to adhere to the base metal.
Electrolosis is doing just the opposite.....removing contaminants from the surface of the base metal, and plating the anode with it. Yes....the anode is sacrificial in the process.

(This is an over-simplified explanation, but the basics are there.)

Roger

Many years ago a British car had an aluminum front end. Where it was attached it rotted due to electrolysis. Stainless would fix this for attaching. (Doc Brenholtz RIP) Attaching aluminum water pumps etc use Neversieze on the threads to make removal a breeze.

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