I don't think the seafoam will get the really hard stuff to come clean that quickly but at the same time it isn't designed as a parts soak.

To get the tons of smoke you have to really slowly add the seafoam to engine while holding the throttle open a bit. Kicking it up occasionally will get you a burst of dark smoke (the white stuff seems to just be the seafoam itself burning) Then let a little more go into the engine till it kills it, after it sits a bit start it up and then blast the last of the stuff out the tailpipe.

The only time I used it was on my old beater of a 280 that would barely idle after sitting for months. After that it idled smoothly.

Sea Foam is

Pale Oil (Machine shop cutting oil) ~ 50%

Naptha (coleman stove fuel) ~30%

IPA (Isopropyl Alcohol) ~20%

Make it yourself.

You can also throw harsh solvents into the cylinders with the oil drain off and plugs out to get the pistons clean. Let it sit/drain through the bottom of the pan past the rings. After a while suck out the remainder in the cylinders through the spark plug holes and maybe chase with a light oil or atf. Change motor oil in car and enjoy.

I was able to give it a bit of a stress test last evening. Ambient temp probably in the high 70s, Sierra foothills, grade steep enough for a passing lane. Floored in 4th and 5th from 2000 -- 2200 rpm and no ping / clatter. 95% sure that it would have done so prior to the SeaFoam treatment in current state of tune so I've got to give the stuff a thumbs up.

Chris