does anyone make a heaterbox/ac evaparator box?

[jackchan]

does anyone sell a new or rebuilt heater core evapartor box that bolts under the dash new/rebuilt for a 87-93 mustang? seems to me it would be a lot simpler to have one ready to stick in, once you removed the dash...........would be easier for me to locate the bolts when reassemblying the dash lol
thanks
Jack