Mr Pain

Ive read lots if threads on here and gotten plenty of useful information. What I plan on doing is the 4th gen dash swap and the entire ac system. So that would be the hvac box, heater core, blower and all the ducting. ..im talking about everything. Iknow already that fire wall mods will be necessary. Such as cutting and maybe welding. If anyone has done this please let me know and I can document everything on this thread. Or if tou know who has done it let me know. Thanks!!

Maverick H1L

iTrader: (8)

There is a thread, "4th Gen Heater Ducting Done Right" I think it's called, where the guy shows how to hack the firewall up for the box. I didn't do mine that way. I cut the box for the firewall to leave the cowl unmolested (I have enough problems over there and didn't need more). You may need to do what I did and make a 1" spacer to go between the box and the firewall.

:edit: You only REALLY need the air box that contains the heater core and the door motors... Nothing else will work and you already have it in the engine compartment. You can even retain the stock HVAC wiring with a simple one-wire modification to the GREEN wire running between 2 of the switches in the control head.

Mr Pain

Thanks Maverick for the replie...good to see someone whos done this and is still active on the site. So you ended up using sone of the 3rd gen ducting? And what wont work? I haven't tedt fit anything yet but I was hoping to use the whole assembly I removed from the 98 TA. Im not sure how I will do things but ill keep you posted and maybe if you have pics of what you did you can post them. I still need to learn how to post pics here lol!!

Mr Pain

Well I got done with the TA. I cut out the frame of the hvac box but I need to clean up the acces metal on the sides. Ive looked at the 91 fire walk and I might have to notch out the top right pass side corner. Ive seen someone do it that just wanted to use the 4th gen heater, it didnt look hard at all. One issue im thinking of is that the water from top under the windshield flows through that tunnel that I need to notch out, but ill look more into it as I go on. Im planning on test fitting the hvac box and with self tapers ill install frame on the 91 just as it was on the TA. Ill just use a good adhesive with the self tapers instead of welding. Then ill simply cut out the middle of the frame and that should do it.... I hope. ..

Mr Pain

86_irocz-28

I did this in my 86 heres the thread page 11
https://www.thirdgen.org/forums/memb...0-86-a-11.html

1983Chimaera

I'm the one that did the "4th Gen Heater Ducting Done Right" thread (https://www.thirdgen.org/forums/inte...r-ducting.html), and have yet to have any issues with water leakage or inadequate drainage from the cowl. So long as you follow my instructions and seal everything properly, the water still has it's drain path and won't enter the passenger compartment. The 3rd gen A/C fan shroud/evaporator unit will work with it on the engine side, it just has to have the upper corner notched for the new heater hose routing. Nothing about putting in the 4th gen dash is direct bolt in, you have to accept that some modification is going to be included in the process, especially to have functional vents.

85Special

Vintage air GenIV will fit our cars, and leave you with a clean fire wall. I have one.

Brando5641

iTrader: (-1)

Not a easy task. There is a lot of cutting and welding involved. You will end up cutting a large sectioin of the fire wall and the wiper cowl. Placement of the ring for the HVAC box is critical.