I did not ask how much they removed when resurfacing. The heads looked good when coming off, so would not think they took enough off to cause a problem with intake sealing. It's possible some coolant got into exhaust pipes when pulling heads, but the smoke never let up. Everything was free of coolant in cylinders.I did not look for bubbles, but also did not run it very long-probably 2 minutes each time(twice). I guess I'll just order another set of gaskets and try again.I may try for a better intake gasket set which may seal a little better. I've built about 5 318's, but never had a problem with them.