93 ranger

I am currently workin on a 93 ranger, 4x4 V6 4.0. I have the engine out and cleaning it up. i was wondering if anyone had any good cheap ideas on how i can imporve it performance but not have to spend a bunch of money on upgrades and such.

to start with:

Use off-road octang booster

Use fresh OEM spark plugs

I gained 5 hp just by changing the fuel filter