Sitting still, with around 95 degrees out, you should have upper 40's, lower 50's at the vent, while moving it should drop into the 30's. I got fed up waiting for a friend to charge my elky, bought a set of gauges/vacuum box off ebay, and a case of 134 from Sams Club. After realizing I had to replace the compressor and the the drier, I got it blowing 44 out the vent sitting still, and while moving when it was 95 out, it would blow 34! Something is wrong with yours. I'd try at least replacing the drier on it (they are around $30), new oriface tube (the elkys was NASTY) and vacuum the system for at least 30 minutes. Put in an oz. or 2 of oil and around 3 cans of R134 in it. I've been shooting for 30-35# of pressure on the low side in R12>R134 conversions...
HTH