GMC Repair: Chevy 350 head issue, last ditch effort, chevy 350

Question
Hi,
i have a 1988 chevy truck 1500, 4x4. I have had plenty of issues with the motor and trans. I put another transmission in, ive also replaced a piston and rings. I have done the heads on the truck a couple times. This time i went to have a mechanic do it because i wanted to be sure it was done right, i have a few hours to drive to college. Well he did both heads, one was cracked i had it replaced. It made the trip to school just fine. But the other night i went out to start it and there was so much exhaust you could almost not see the truck. It reminded me of how it was with a cracked head. So i took the cap off the radiator to look for bubbles, The coolant was low, i added some to top it off. There were very little bubbles. I gave it gas and it would bubble more, just like it did before i had the heads done. So im wondering, can anything else cause bubbles in the radiator? I drove the truck home today, 180 miles, it didnt overheat once, so im a little confused. Or can it still be a blown headgasket and not overheat? if so what would cause my truck to keep blowing headgaskets, or was it a mechanics fault? Any help would be appreciated, thanks
Kolby

Answer
Perplexing dilemma you have. First things first. The head gaskets...not all are perfect and/or made the same. We have the human factor working here. However, New ones can be bad. I would use the warranty and tell the parts people that you had a mechanic do the work. Make sure that you do tell them. Did you replace both the heads? Anything that you replace that has a matching part, and comes in pairs or more...you should replace both or all at the same time. If you only replaced one head you need to consider, are the wear on the springs the same, the wear on the valves, valve seats, is the valve clearance the same? I would consider the block as well. A last ditch effort would be to tray some stop leak. I have used this before with good results, but I do not recommend. I would buy a can of it and keep it with you. Try bringing the vehicle up to operating temp and running the RPM's up while you are under the hood, checking for leaks. Should look for very small discharges of coolant.