1972 Plymouth Satellite Not cool air coming out.

Hi, my evaporator is in the front and condenser is in the back. System converted over from r12 to r134. Everything was fine for 6 months. Now im not getting much cool air inside car, however, expansion valve is cold going in but then not getting any cool air coming out of condenser and inside air just a little bit cool. The gages are reading 150 high side and 30 on suction. Could the blockage be in the evaporator or condenser. Could ither one be the problem. Also, I do not feel alot of heat other than the first tubes and no more heat thru condenser. In the site glass you can see maybe 1 or 2 bubbles but not much. Also, could just being converted cause these issues in general? Thank you for any response.