I have a 91 F-250 with a 351W EFI, it has the stock computer with SD and as I look into putting in some upgrades I'm realizing that the SD is kinda restricting, especially when looking into cams, so I've been considering converting it to MAF with a kit like this F Series Mass Air Conversion Kits . My questions are has anyone put this, or something like it, in their truck? Does it help? Was there a noticeable power difference?




1991 Ford F-250 XLT Lariat regular cab 4x4, Mack Bulldog hood ornament and over sized aluminum wheels with BF Goodrich T/A tires. It has an almost stock 351W EFI, Hooker shorty headers, 3 inch stainless steel true dual exhaust with Flowmaster super 44s and 4 inch rActice polished stainless steel tips.

 

I have the one that Ford put out awhile back for the 5.0/5.8. I spliced the wires and re-routed the injector timing to the 351`s against Fords advice. They said that it didn`t make much of a difference because they switch on and off so fast,and that I probably would mess it up. But it doesn`t make sense to me to spray fuel with the valve closed. I did a pro job on the wires and it works real good.

 

Maybe at drag race RPMS but on a street vehicle that's got to idle... these guys are idiots for suggesting that. I also have a Ford kit on my truck and yes the first thing I did was rewire it to match the engine, and guess what the idle is as smooth as glass. There have also been several others here over the years that have done their own conversions or used a kit with the wrong firing order and had severe idle problems and low power output.. all of which was fixed once the injector firing order was changed to match the engine.

As for the kit itself it won't make any difference in power on it's own, but put a cam in the motor or change the heads and exhaust and it'll work much better than it would with the stock computer.

 

Thanks y'all