heater box in formation , please

hi guys , just wondering is a Non a/c heater box from a 66/67 B-body the same as fitted to 68/69 b-bodys ,if so !! to swap said non A/C heater box into a A/C fire wall do i need to drill any mouting holes through the fire wall or do they use the a/c box holes , any info would be appreciated

a non a/c 1966-67 will bolt right on to a 1968-69 non a/c car. there are some differences with the cable control on the box but will work. the firewall for an a/c car has completely different mounting points than a non a/c car. so you can not just bolt in a non a/c box in an a/c car and vice versa.

thanks for the quick reply !!