V8 swap

[RFD2]

My 1986 has factory air. Have seen the heat gun/oil filter technique and like it. Before I do that has anyone attempted that on factory a/c box? My concern is restricting airflow to evaporator so much it becomes

 

[85_Ranger4x4]

I have never heard of anyone having problems by restricting airflow.

 

[RFD2]

Ok thanx, it just looks like the non-a/c heater box doesn't protrude as far forward of the firewall as mine, Again, living in arizona a/c is a must. I'm about ready to start acquiring parts and don't want to have this become major issue