'88 80Q heating problem

[linc]

Howdy folks, working on an '88 80 Quattro.  It was a Texas car, so 
didn't see much in the way of winter.  However, I live in Ohio.  The 
interior heat only feels warm after a long time, and only when the temp 
guage is up to about halfway (where the blowers kick on).  It supposedly 
had a new thermostat in it, but I bought one and put it in myself to be 
sure.  I also flushed the heater core both ways with a hose, and bled 
the system for about an hour to make sure there wasn't air or crud 
trapped in the heater core.  It's warm enough to defrost the windows and 
take the chill out of your toes, but my friend's newer 80Q will cook you 
in about 7 minutes.  I would like mine to work like that.  Any pointers 
greatly appreciated.

My next step is to tear into the dash and make sure the fresh air vent 
and blower box is all working right.  I have a theory that cold air is 
coming in all the time.

Really like the 5-cylinder life though, and the heated seats help :)

Linc