MAF Conversion

[jk2011]

I have an 89 F-250 with a 351. It's been sitting for over four years. I hope to start rebuilding it in the near future with many upgrades, one of them being a MAF conversion. My questions are which size maf sensor, which computer, and which injector wires should I be looking for. Also should I upgrade to 24 pound injectors? Other upgrades I'm considering are a 3.85 stroke crank, Port and polish the heads, new lower intake, and possibly a very mild cam.

 

[Skandocious]

Your best bet is to find a donor truck for all of the parts. The computer will need to come from a truck that has the same engine, trans, and I believe drivetrain (2wd/4wd) if you've got shift-on-the-fly. If you can't find a donor then you might be able to run a custom program with something like a TwEECer.

 

[jk2011]

Ok. I was planning on searching the junk yards anyway, but I'm not sure if I'll be able to find all I need. I'd been wondering if there was something out there to reprogram, but I wasn't sure where to look, so I will definitely keep and eye on a TwEECer.

 

[89PSD]

what trans do you have?

go on ebay and get a 89-93 mustang 5.0 wiring harness and mustang a9L computer, then get a 75mm mass air meter and fab u some sort of Y pipe for the intake to throttle body to hold the meter. if you plan on stroking/cam, and a port job i would go with 30-36lb injectors.

heres a link todo the conversion
http://bjoern.brembs.net/cars/maf_conversion/

I plan on doing that soon. even though its for 5.0s, it will have no problem controlling a 351.
this was is cheaper and more available for parts.

 

[Lost]

ABout ANy 94 newer 302 equipped truck will have the harness you need . As for the 351 ecu Good luck if you dont live in CA .

The stang parts r easy to find But I like the swap whole harness and be done Approach when using truck parts Plug and play . I have done several 351 and used 302 ecu till got a 351 one Fine for normal driving .The Stang ecu can be found real easy and be found Modded quite often Good luck

Word of note My truck has 1 o2 some have more and 96 newer r OBDII avoid them more wires

 

[flareside_thunder]

Also, check corral.net for parts for your MAF conversion. I don't really agree with the 30-36lb injectors....but that's just me.

 

[conanski]

A stock or mildly upgraded 5.8 will run on a 5.0 EEC no problem, my truck had that exact setup for years and ran great. "Mildly upgraded" is ported heads, a cam, and full exhaust and that will run on 19lb injectors too believe it or not. Bigger squirters aren't needed until you get bigger heads and intake, and that is also when you'll need a tuner to make it all cooperate. On an older truck with an all mechanical transmission the mustang MAF setup is the best way to go as it is also what is supported by the aftermarket tuning systems. For best results you want an EEC and MAF meter from the same vehicle, and that's because the computer holds the meters calibration data so another meter obviously won't match. There are some aftermarket meters that are "calibrated" for larger injectors and while this sorta works on a motor that is still at the stock displacement it doesn't produce very good results on deep breathing strokers or motors that move significantly more air than stock.. like on the order of twice as much or better.

For the wiring you could salvage what you need from a MAF truck, there will still be some patching to do with this as the harness on these MAF trucks run through connectors that don't exist on the older trucks, but the total number of wires needed isn't huge so it's not a big deal IMO. Some wires in the '89 truck harness will have to move as well because the mustang EEC is pined differently, but again that's not a hugh deal because the EEC connector comes apart to allow the wires with pins attached to be moved around. I have a spreadsheet with the EEC pinout differences between the truck and mustangs if you're interested.

There are no alternative lower intakes for this motor that are compatable with the stock truck upper. If you want better flow I suggest you simply port the lower as there is a lot of potential left on the table. The exits in the lower in particular tend to narrow down near the gasket surface and simply opening these up to match the port size and location in the heads will produce significant gains. The stock heads are much too small for this motor and the exhaust side in particular is really bad, but even so it's not too difficult to get 300hp out of them, hog the exhaust side out as much as you dare and then pocket port and straighten the intake as much as possible. Alternatively you could try to find a set of GT40s from a '96-97 Explorer 5.0, those heads have larger valves and flow about as much as a well ported E7s, so you can save yourself some work.

 

[jk2011]

Thanks for the info. Hopefully I will get started on this in the next few months. I may be back with more questions when the time comes!