A problem you may run into is what is called "false seals". As gaskets and seals go bad due to age and abuse they would normally start leaking/seeping. The grunge you want to remove has "packed" the bad seals so when you remove the grunge, your false seals goes with it. All of a sudden you've got a clean engine leaking all over the place. Gaskets and seals can be replaced much easier than a hard to find engine, It's par for the course and a good reason to spend time in our shops breathing fire into these old iron horses.
