I just purchased an '83 Chevy G20 conversion Van w/ a 6.2 diesel engine. So far I love this beast, but I'm somewhat disappointed with the A/C (I live in FL and it's a MUST!). The A/C doesn't seem to get very cold and only improves somewhat when it's rolling at 50+mph or when accelerating hard and the rear air doesn't seem to be working at all. It was converted from R12 to R134a and (supposedly) has a new compressor and dryer. I was told that Chevy / Delco AC systems don't cool as well as those from other mfg's. Is there any truth to this? ANY troubleshooting input regarding this (what to check first, possible upgrades, ideas, flat rate fees, etc.) would be greatly appreciated.