88 Chevy 1500 Heater Core

[texasprd]

I'm trying to replace the heater core on my '88 Chevy 1500 and I need some help.

The Haynes book says to detach the heater/plenum box from the firewall, unbolt part of the dash, and drop the heater box, before removing the core. I tried this, and I don't see any way to do this without disconnecting the hard A/C line from the accumulator (?) - the hard line U-turns from the accumulator and goes through the dash, apparantly to the A/C core.

Is it possible to remove the heater core by simply removing the 4 or so screws holding on the bottom of the heater box? Is there enough room between the box and the floorboard to get the core out, and is there enough room to get one's hand up in the box and remove any hold-downs?

Who's done a heater core on a similar vehicle, and how did you do it?

You help is greatly appreciated!!!