Chevrolet Repair: engine pressure, valve rocker, thanks alot

Question
I just put a 305 in my 83' chevy, and i've tried for about a year and a half to get it in time, and about a week ago i finally got it so it would at least run, and for some reason there is steam comin up out of the carbrator while it's runnin and it has lots of pressure in engine, and someone told me it might be that a valve isn't sealin right, but i was hopin u could answer my ? if u got time. Thanks alot and i hope that u can figure it out.

Answer
Hello Justin,
I doubt that is steam. I would suspect it is vaporized gas.
It may just be that the timing is advanced too much.
If the engine had the camshaft replaced, the timing chain may be off a link.
One of the valve rocker arms may have been adjusted too tight.
If it is a valve problem, concentrate on the intake valves. It will be one of them.
Van