Are you looking at installing the 67-72 Surefit unit ? If so, you do have an option as far as the firewall is concerned. The Surefit units come standard with an ABS firewall cover for the area of the factory heater box and an ABS cover for the blower motor area. Now, as i am planning to do, you can run a 4-way Bulkhead ( such as the 384600-MBA ) on the firewall with this unit BUT you MUST tell them you plan to do so that they can configure the lines correctly on the unit. Then you can go ahead and fill all the holes for that area. Installing the bulkhead is as simple as drilling (4) 7/8" holes using a template. This info comes straight from the tech dept @ Vintage Air. If you need anymore info, give them a holler !! Great bunch of guys to speak with ! Good Luck and keeps us posted on the install !!
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Chris
click here to see my buildpage
http://67-72chevytrucks.com/vboard/s...d.php?t=394656
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1979 C10 Silverado Big10 SWB
Factory 454/400
Cardinal Red/Santa Fe Tan (original paint)
1969 Camaro X44 LS swap
1968 C10 SWB Fleetside (SOLD)
468BBC MultiPort TPI / Dynamic EFI P4
Black/Black
1963 Nova SS convertible (SOLD)
194 I6/ PowerGlide