Okay... lets see... for all out performance?
Get your heads polished and ported.... you can have your intake smoothed out as well if you like... and get the inlet to match a larger throttle body.... all can be done at a machine shop.
They have cams available for the 4.0. Comp Cams and some other company make them... they require custom length pushrods which can be purchased a variety of places.
Get that Chrome Moly stuff for the pushrods, its lighter wieght a supposedly stronger.
Dont bore the 4.0, I asked about this already and it can only be bored .04" which is used to bore out any scratches later on...
Lifters should prolly be replaced... and you can get new heads if you feel they need replacing... also... on a side note... if you do what I did... and have a 91-94 Explorer... you can put newer 98+ heads in and gain 1 point to your compression.
An Oil cooler or deeper pan is kinda up to you and what you use your truck for... transmission coolers are cool too. You might have one already though...
Replace the thermostat... but keep it at 195... or if it get really hot in your area, you can try a 180... but 195 is the recommended.
MAS should probably be held off till last...a the gain are small if you havent freed up more power elsewhere... if you do all of the above mods... it probably would justify one... get the throttle body first though... as far as brand... I like my GMS MAS. And the Edelbrock/BBK TB has worked out well.
Go for the Borlas if you have cash to spend.
I had a hell of a time trying to find a set... so I gave up on bought some BBK headers. They are all the same as far a performance goes. You pay for the material. The Borlas are stainless steel. The BBKs are something else... but chromed (and cheaper). You cant see em anyways... so its up to you.
Anyways... get an aftermarket computer chip too... just as long is its not a JET chip. Those suck. If you can find some of my earlier posts... I have done dyno runs with my listed mods. The results were disapointing... but I believe that I cant really free much more HP up... and that I might need to get a cam and port and polish my heads to see my real gains...
