Engine Question...- internal cleaning?

[NC_John]

I just ordered the parts to pull and reseal the 350 in the '70. Its running great and doesn't seem to burn any oil, but leaks a ton! I have zero tolerance for leaks so its coming out to be resealed.

I've got new gaskets all around, new seals etc. While its open I'm replacing the timing set and oil pump but nothing else. If I can get another year or two out of it before a real rebuild, I'll be able to get a bunch of other stuff done on the truck first.

I'm going to pull it out of the truck to do this but before I yank it, I'm wondering if there is anything I can put in the oil and coolant and run through it to do a "pre-cleaning" to try to dissolve what I would expect to be a lot of sludge and crap in the oil galleys/passages and in the cooling jackets. I usually don't like that stuff, BUT, since the engine is coming out, I should be able to do a decent job of making sure its all drained out and cleaned out before I button it back up.

Worth the effort or just scrape out what I can get to??