https://www.ford-trucks.com/forums/1...l#post15091764


Perhaps this will help someone living in an area where emission testing is still being done.

 

I think those years of 4.9 production were the "dark years" of the engine's lifetime. That was when the company was trying to integrate engine controls to entirely computer control, while at the same time hanging onto the past technology with a complicated feedback carburetor and a distributor. With a series of vacuum switches and other vacuum controlled gizmos (evap, air pump, EGR, A/F ratio, spark) the engines had become laden down with hoses, wires and stuff.
I had a 1985 and was intimidated enough with all that stuff to just leave it alone, lest I mess it up, even though I understood how every component functioned. So this would be a good investment if you have to go back to stock for those years.
The era of EFI actually simplified everything and technology took a leap forward in 1987 and later.

 

SOLD!!! Thank you.