wwerner

I have a 92 f150 5.0 5 speed,I have a built bottom end eagle 331 stroker kit out of a mustang my current 302 is burning oil and has low oil pressure at idle when warm so I was gonna do this 331 swap with the comp cam 31 255 5 and trickflow 170 tw heads what do I need to do to make the speed density work with this? can it be done with 24lb injectors or should I go back to a good ol' 4 barrel? I like the efi waaayyyy more than a carb but if it's easier... please help I'm at a loss here

Chris_1

iTrader: (1)

Speed density does not play nice with real lumpy (low vacuum) cams.

wwerner

I heard that so I went with a decent truck/efi friendly cam ... but with he added air flow would it run with bigger injectors? Or could I get the sd computer revised? I'm just kinda lost I can't find much about tuning these efi systems

Chris_1

iTrader: (1)

The computer should do it's thing (fuel trim) based on the O2 sensor readings I would think.
Read up a bit on fuel trim maybe.
The other slightly complicated alternative is to steal the wiring etc. off a later truck with mass air.
You may need bigger injectors to keep up, I'm not that well versed on other than stock setups.

BLDTruth

If you want to do any fancy engine upgrades you will need to convert to MAF or carb it - there isn't really any way around it. The SD computer is just technologically inferior.

The only way to convert to MAF on a 5-speed is to pull a computer from a similar year mustang with a manual transmission. You'll need other stuff too like the air tube/sensor and some wiring but the computer is usually the hardest part to find. They also sell kits on ebay but they run $1000 and up.

If you can find a MAF computer on an OBS 5-Speed (or I guess an AOD would work too) F150 then please let me know - I don't think they exist.

wwerner

What if I were to buy the painless harness and a computer for a similar year mustang? Would that work? AND by doing all this could I then get a tune?

BLDTruth

I've exhausted my knowledge on the subject unfortunately - I read up on the conversion and found it to be not worth the money for my uses. There are a ton of threads on the subject out there, not necessarily on this forum. I'd try googling "Bronco MAF conversion" and you will come up with lots of results with a lot more info than I can give.

Good luck and let us know how it goes.

wwerner

What about swapping to a carb what would I have to do?

BLDTruth

Complete retrofit of the fuel delivery system for starters.

It would be way more beneficial to bite the bullet and do the MAF conversion - if you can source parts and install them yourself it can probably be done for $400-500. And then you have the ability to do whatever you want going forward.

There's always the option of just throwing it in there and seeing how it runs.

Chris_1

iTrader: (1)

A lot to be said for building things stock, or at least close to. Changing something isn't that much money, but then you have to do that, and then you have to do something else, and then something else, and a simple upgrade starts turning into a money pit. And then if you have an issue, nobody can figure it out and then the mechanics start scratching their heads and saying things like "well... we can try this or that, but I can't guarantee anything..." all at 80 or 100 $$ an hour.
All fine if your pockets are deep and you don't care, but be prepared - modifications almost always cost way more than you originally thought they were going to.