to A/C or not to A/C?

You need to very little to the firewall to bolt in a non AC heater box and blower motor.

Non AC heater box bolts right in. You need to do some mild fabbing for the blower motor.

Power loss is minimal when the AC is turned off. Weight is only an issue is you are fighting weight to wring out every 1/10th in the 1/4…..