Have a 1986 F150 EFI 5.0 with a T-18. Motor has 160k original miles and is bone stock untouched. It also needs new valve cover gaskets and has an oil leak at the rear of the lower intake manifold. Going to be R&Ring the lower manifold and valve covers in the next couple weeks. I'm new to the older motors and am not familiar with all the little tricks. Anything I should make sure to check out or any performance upgrades I can do while I'm in that deep? No head swaps at this point. Some porting working on the manifold would be easy for me. Also plan to check compression and put some new plugs in it.

 

Not a lot you can do to upgrade that. K&N filter for starters and remove the silencer from the air box. It's got a flat tappet cam that's specs small by small. Heads are nothing to write home about. They're either the earlier open chambered types or the high swirl E6SE's.

 

You might benefit form a set of high ratio (1.7:1 ) roller rockers. Easy enough to do, and not real expensive or radical.