For my backing I used lawn equipment pre filters. The old twin 600cc hondas gc620 iirc (flat panel panel, not Donaldson af style)had huge ones but for smaller parts I used whatever fit.
Cleaned all the old foam off with a wire wheel grinder...
You can use any 1/4 inch single sided glazing foam or some backer rod. Yes the brackets are different. Now don't quote me but I think the pickup uses a smaller mounting 4 bolt then the 4runner. When I was peicing my system together my dad...
I'm getting ready to remove my OBA and reinstall all my A/C in my '86 4Runner. Glad this thread is alive! I've slowly collecting the parts I need.
What foam did you use for the box around the evap?