My F150 engine, bone stock 5.0 SD system, is getting tired after 80k miles and years of sitting unused before last year.
The engine is not so much tired I suppose, but the seals are shot. It leaks everywhere and the valve seals are gone.
So I want to do a rebuild, or re-engine.

My plans are:

Late 5.0 roller block
Very mild cam, either stock 86 HO cam or aftermarket RV roller cam.
331 crank (Cast crank, I beam rods, flat top pistons)
Mild aluminum heads, something along the lines of 160 cc, 1.9/1.6 valves.
Shortie headers (1.5" primary that bolt to stock exhaust)
ORP
3" single into 2.5" dual exhaust, either turbos or Flowmaster.
Roller rockers

Things that will NOT change:
Throttle body
Injectors
Intake
Computer
Speed-density system

Am I asking for trouble, or have I kept it mild enough to not pose a problem for the computer.
It is said that you should not do any mods to an SD system without converting to mass-air...
I find this hard to believe. Have any of you done this?
Thanks!
Dave

 

As soon as you try putting anything that messes with more air or fuel... you'll have trouble with speed density.

Your best bet is switch everything over from a late model mustang... engine (including cylinder heads), cam, harness, computer, etc, etc.
It's apiece of cake... done it myself.
Then, you can do anything that the 5.0L mustang guys do and make a ton of power.

 

Ford Racing has the Mass Air conversion kits available for your truck. Part #'s are M-9000-T50 for manual trans M-9000-T51 for auto trans. The kits come with new PCM, wiring harness, mass air flow sensor, heavier fuel injectors, and air cleaner assembly. Put a kit on my "94 Lightning and it makes quite a difference even without engine mods. Kits are arouind $750 and $795 respectively. It is a good kit for the money and saves you time trying to piece together parts and hitting the boneyards. Good luck and have fun!

 

Either do the factory mass air conversion, leave it stock or do a full conversion to a HO engine and computer system.
The reason is your truck's computer system is not the same as later FI.
Your system 'batch fires' the injectors that the later systems don't do, and has only one oxygen sensor and the old cam fire order that the later system don't use.
The other option is to go 351w with it's same type control system and /or changes. It is nearly a bolt in change.
Sorry it's not as easy as you thought is might be.
For a moment I thought I was on the Maverick board!

 

Thanks for all the input.
I guess I need to change my thinking.

Does anyone make an ORP for a 90 F150?

Thanks
Dave