~Ok here’s the deal I have a 1979 Honda Civic. About 4 years ago I had the motor rebuilt. It never did run right after that. Hesitations…and head gaskets that kept blowing. Well, I found out later that they never milled the head, and anyways the warranty ran out. It sat for almost a year with a blown head gasket, I finally got it back in the shop at another mechanic, still did not run right, hesitation, getting too warm, found a leak in the radiator, got that under control, yet it was still hesitating and blowing head gaskets! ?? I had brought it back to get the head re-milled, and more head gaskets, and flex bolts? This mechanic has done all he knows to do, and I’m still under warranty, but he refuses to touch it. It does not over heat, I’ve got that under control, It starts up fine, drives like a dream, lots of power (for a civic 
yet every now and then it hesitates and when I start it up after its warm a big cloud of coolant out the tail pipe. And it’s coughing and weezing. NOT OVER HEATING I want to emphasize that. This will happen about every 3rd day. Cracked head doesn’t let you have a perfectly fine running car for a few days then not can it? PLEASE HELP I LOVE MY LITTLE CAR AND DON’T WANT TO GET RID OF IT!!! 
I registered it as a classic this year.
I just hope that you don’t rely on this car for transportation!
As to “classic” status, I seriously doubt that this car will ever be a collector’s item. When you consider the amount of money that you have sunk into this 30 year old car, coupled with the fact that any new car would be safer by a measure of light years, I would advise you to park this car and buy something newer, safer, and more reliable.
This era of Honda was prone to problems. However, if the head gasket job was properly performed you should not be going through this kind of grief.
There’s a lot of the repair process that is unknown to me but some points to consider are:
A cylinder head can only be milled so many times and only so much material can be removed. Take off too much and problems will occur.
Around 500 miles after a head gasket replacement the head bolts should be retorqued and the valve lash should be inspected/readjusted as necessary.
A new head gasket should be coated with aerosol Copper Coat. While not often done, it can help immensely on aluminum head engines. Some car makers (Subaru for instance) have even recommended this.
Hesitation can be caused by:
Ignition timing retarded too much.
Carburetor accelerator pump circuit problem.
Air leak; meaning vacuum line, carburetor, or an intake manifold fault such as a warped flange. Inspection of the manifold should be part of a head gasket job and intake manifold often need to be milled just like a cylinder head.
(I would point out that there were a fair amount of problems with this era of Honda anyway but still, I’m inclined to think the mechanic(s) are missing something rather than the car itself being at fault.)
And just to clarify; is this cloud of smoke out the back white in color, black, or somewhat bluish/white in color?
That was helpful…not.
What about a PCV valve? Could that be causing repeated head gasket problems?
Google “rebuilt Japanese motors” and find a place to sell you a warrantied rebuilt motor.
Also, keep in mind that maintaining a 30 year old Honda is a hobby, not economically sensible transportation.