a.c & stock heater firewall the same?

[blazer2007]

Will a ac heater unit fit in the firewall that had a stock non ac unit and vice versa on a 78 truck.It looks like the ac unit is larger on the firewall.I,m talking about the fan and box unit that bolts on the firewall in the engine compartment

[blazer2007]

I found a pic and the ac unit looks quite large,is there a plate to change from the ac unit to a non ac unit ?

[80SPORT]

The hole for the a/c trucks is different than the standard units but it is not hard to modify either way as the firewall is flat in that area.

[95 S_Trucker]

the hole is in a different spot and is in a different shape, i put ac off a 79 on a 78, and the 78 did not have a/c previously.

i made a template off the a/c cab. layed it on the other cab, cut the whole bigger and filled in the rest, drilled some holes and mounted up the box

79 firewall



79 firewall with template



78 firewall after modification:



all painted



the box

[blazer2007]

Ok thanks,it just that a friend has a truck up north but he doesn,t want the ac [no use up there]and he will trade me for mine[and i need air down here in the summer]We were just wondering how they would inter change but it looks I have to do some cutting and he has to make a plate

[Keith Seymore]

Originally Posted by 95 S_Trucker

the hole is in a different spot and is in a different shape, i put ac off a 79 on a 78, and the 78 did not have a/c previously.

i made a template off the a/c cab. layed it on the other cab, cut the whole bigger and filled in the rest, drilled some holes and mounted up the box

79 firewall



79 firewall with template



78 firewall after modification:



all painted



the box

Nicely done, and good input, too.

I like the note on your template...

[95 S_Trucker]

Originally Posted by Keith Seymore

Nicely done, and good input, too.

I like the note on your template...

when there are other people in your shop things tend to disappear sometimes, and there was a 3 week period between making the template and cutting the cab