The biggest problem on these systems is the ductwork sux. None of it fits well, and 9 times out of 10 none of the pieces are actually fitted together, so most of the air is blowin out under the dash. You'd be amazed at how bad the ducts fit...or don't fit, from one piece to the next.
I've also heard of folks using the later blower motors, but I think if everything behind the dash is connected properly, and the vents on the cowl are operating correctly, the HVAC system works pretty well.
______________
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"