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302 to 5.0 HO EFI Swap Advice Needed

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  1. #1

    Default 302 to 5.0 HO EFI Swap Advice Needed

    An EFI conversion is definately on my list of things to do with my 1976 302, but it is a bit down the road so I haven't done my homework yet, just some preliminary Googling. However I have come accross a deal I don't think I can pass up, so can you guys tell me if I should get the parts off of this 1992 5.0 HO automatic. I mention automatic because I heard the more desirable swap is for the manual (with the A9L computer) so you don't have the tranny sensor throwing a check engine light since you have no where to plug it into.

    I am hesitant because the HO's came with roller cams, and I think mine is a flat tapped, (though I read somewhere that maybe all 5.0's were HO during that erra 88-91) also the HO's have a different firing order (same as the 351) right?


    Upper Intake
    Lower Intake
    Throttle Body
    Wiring Harness
    ECU E9AF-14A624-AA
    Fuel Rails (maybe)
    Fuel Injectors (maybe)
    Fuel Injector Harness (maybe)

    No Mass Air Flow Meter (Bummer)


    1. Does the 5.0 have a flat tapped cam and the HO has a roller cam, among other differences?

    2. Can I mate the 5.0 HO distributor with my 302 stock cam, and will that change the firing order?

    3. Can I use my stock D50E A3B heads someone said they are better than the 5.0 heads? I do own a set of 5.0 E7TE ie 1987 heads as well, would I have to use those instead?

    4. I really don't know what determines the firing order is it the distributor, or is it the distributor/cam combination?

    I don't want to get these parts if it means convertng my engine to a roller cam engine, if I have to do that I might as well just drop a complete 5.0 engine in. But then again I have no idea what I am talking about so somebody set me straight, please.

  2. #2
    Join Date
    Mar 2002
    Valley, Alabama


    I'm far from an expert but I'll give it a shot.

    1. The 5.0 came in plain vanilla and HO (Mustang GT and others) and starting around 86 or 87 they all have roller tappet cams.

    2. You can use your flat tappet cam driven distributor with your roller tappet cam but you MUST change the distributor drive gear to one made for use with the roller cam. No, the distributor doesn't determine firing order. That's done by the cam.

    3. I'm not sure about the heads but I'm pretty sure you would want the later model ones. They came a long way in meeting smog requirements in those 12 years. I also think you'd have a problem with the type of rocker arms on the 75 heads vs the 87 ones.

    4. Covered in #2.

    You don't have to convert to a roller cam for EFI. There's an article in a previous Mustang Monthly where they did the swap on a 60 something model 289.

    David G.
    1969 Mustang Sportsroof
    1998 Mustang V6 Coupe
    2002 Supercrew Lariat
    Mustangsandmore Member # 1964

  3. #3
    Join Date
    Oct 2004
    Medford, OR


    Everyone is on a budget of some sort. Your best bet in my opinion is to yank a complete motor/harness, and everything else you might need for the swap. You might have to source a computer, but in the long run you will save money......ask me how I know
    '64 Falcon Futura 2dr hdtp. 289 4 speed.
    '90 Mustang LX Coupe. 5.0. Aod.

  4. #4

    Default EFI Parts List

    What the he11 for $100 bucks I went ahead and bought all this stuff. I know what you are thinking, are you kidding us, you asked all those questions for $100 bucks, you need to get smacked upside the head... whoa wait a second, don't tell me you guys never bought a part for $50 bucks and spent $500 trying to get it installed and working, LOL...

    1. Upper Intake
    2. Lower Intake
    3. Throttle Body
    4. Throttle Position Sensor
    5. Idle Air Control Sensor
    6. EGR Valve
    7. EGR Valve Sensor
    8. TFI Distributor
    9. Spark Plug Wires
    10. Fuel Rails
    11. Fuel Injectors
    12. Fuel Injector Wiring Harness
    13. Main Engine Wiring Harness
    14. ECM - Computer
    15. Oxygen Sensor(s)
    16. Coil
    17. Hardware

    No Mass Air Flow Meeter, (that's the only biggy that's missing) and the air intake tube, etc. At this point I am thinking I may consider trading this stuff for a non HO setup to keep my conversion simple, any takers?

    More pictures available here: Small Block Ford 302 V8

    Last edited by Gregski; 08-08-2010 at 01:16 AM.

  5. #5
    Join Date
    Jan 2009
    Pittsburgh, PA


    For what it's worth, that upper intake is a '94-95 Mustang HO unit. The angled "elbow" between the throttle body and plenum is different than the '87-93. I think Ford changed that for fitment purposes in the '94-95's. Throttle bodies may be different too, can't remember.

    May or may not make a difference when chasing parts.
    MotoArts Decals and Signs
    - '90 Mustang 5.0 7-Up convertible, mainly stock.
    - '71 Mustang Sportsroof, 351C/4 speed car, should be 460/C6 when it hits the street... or maybe 351W roller...
    - '66 Sunbeam Tiger Mk.IA, survivor.

  6. #6
    Join Date
    Jan 2004
    Kenora, Ontario, Canada

    Default EFI swap

    I have a 5.0 l EFI in my '78 K.C. The older style plenum just fits, and I think that the later style pictured in your info is a better deal. I spent extra money buying an elbow and other parts to achieve the same thing. Not getting the MAF sensor may turn out OK, as you might wind up building a cold air box, and the Ford one might not fit with what you do.
    Attached Images Attached Images

    '78 Mustang II, modded King Cobra, 1987 5.0 L EFI, T-5, Versailles 9" posi, Granada 11' front rotors, BFG T/A's on 15" American Racing Silverstones

    '67 GTA 390 Fastback

  7. #7
    Join Date
    Jan 2004
    Kenora, Ontario, Canada

    Default more

    If you are going to use this setup on the engine you have, use the E7TE heads. Ford used those after a screwup in 1986 with a poor head design. I've read that they are the best, inexpensive head to use.

    '78 Mustang II, modded King Cobra, 1987 5.0 L EFI, T-5, Versailles 9" posi, Granada 11' front rotors, BFG T/A's on 15" American Racing Silverstones

    '67 GTA 390 Fastback

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