Ford 351w to 408 rebuild questions.

Discussion in 'Shop - Engine' started by Sites, May 8, 2008.

  1. Sites

    Sites Member

    Joined:
    Mar 16, 2002
    Location:
    San Diego
    My motor has almost 130k miles on the stock 351w and I'm looking to freshen it up a bit. I installed a pair of AFR 185 aluminum heads and a CompCams Xtreme Energy Cam (35-255-5) that would be carried over after the bottom end has been rebuilt. The fuel system is the factory speed density set up and the only thing i've added is an adjustable fuel pressure reguator and the intake is the stock Lightning one which is supposed to flow a bit more than the regular 351 EFI intake.

    So my question is, does anyone have experience or recommendations on a reasonably priced 408 stroker kit?

    Does anyone have experience with retaining the factory fuel system? Can I get decent power with it? Any recommended additions to aid in tuning?

    What is the highest compression ratio recommended if I still want to run 91 octane?

    What is a reasonable hp/tq expectation with what I'm trying to do?
    Last edited: May 8, 2008
  2. jeff

    jeff Super Moderator

    Joined:
    Apr 1, 2001
    Location:
    California
    I built a 408w for my prerunner. It's running Canfield heads, a custom Jay Allen cam, Vic Jr manifold with a Holley TBI EFI system. After a few dyno tweaks it made 500 ft/lbs and 500hp on regular 91 octane. If the EFI takes a total poop in BFE I can swap a Holley carb over in about 10 minutes.

    Try here for info: http://www.sbftech.com/

    Aloha
  3. partybarge_pilot

    partybarge_pilot Well-Known Member

    Joined:
    Feb 19, 2002
    Location:
    Leucadia, CA.
  4. Sites

    Sites Member

    Joined:
    Mar 16, 2002
    Location:
    San Diego
    Jeff,

    Which model Holly TBI did you go with? Summit has them for $1599 for the entire kit, which sounds good. How was tuning?
  5. jeff

    jeff Super Moderator

    Joined:
    Apr 1, 2001
    Location:
    California
    I'm running the Commander 950 system with the 900cfm / 85pph injectors. The Holley system needed one major upgrade to allow for proper tuning. The regular O2 sensor isn't up to the task, I had to purchase the wide band upgrade. Without it tuning the motor is pretty much impossible. I found Amazon.com to have the best Holley prices. On the wide band O2 kit alone Amazon was $150 less than Summit (no idea if it was a typo or ??) but Amazon was the cheapest I could find. I am running the largest injector that Holley offered in TBI kit form. The big reason I chose the Holley TBI system is I can buy basic replacement parts for it at the local parts store. The TBI body is easily swapped out... I can disconnect and remove the TBI (4 nuts), bolt on the carb using the same hardware, adjust the fuel pressure down a few PSI at the regulator, hook up the supply, cap the return line, connect the throttle cable and off I go.

    Aloha
  6. j10-401

    j10-401 Active Member

    Joined:
    Dec 8, 2007
    Location:
    Valley Center CA.
    If you wanted to run the factory fuel injection, look out for how big of a cam you are running. Being that the speed density system, or map sensor relies on a vaccum signal to adjust fuel trim a large cam with a low vaccum signal will cause a very rich condition at idle. However there are kits that convert the pre obd 2 system (map sensor)to a mass air flow sensor out there.
  7. Sites

    Sites Member

    Joined:
    Mar 16, 2002
    Location:
    San Diego
    Im well aware of the speed density issue with the factory setup, which is why I went with the aftermarket cam that I currently have.

    After looking into the Holley TBI EFI kit that Jeff is running, I think I'm going to pick one up next week.

  8. stevenc

    stevenc Member

    Joined:
    May 16, 2008
    Location:
    Riverside Ca
    In some ways the compression you can run depends on how well you tune it. You can run 10:1 compression, maybe more if you tune it and combine it with with a good camshaft. For example, I am going to be building a 460 with Iron heads and a custom camshaft grind @ 10:1 compression. I am however going to be building up my own EFI system by doing the following:

    Step 1: Drilling and welding injector bosses in an edelbrock aluminum intake. Also building a fuel rail mounting bracket.
    Step 2: Obtaining a EFI elbow such as the following:
    http://store.summitracing.com/partd...1&part=EDL-3849&N=700 400065 115&autoview=sku
    Step 3: Using a bored LS1 Style throttle body.
    Step 4: Last step, build a megasquirt system: http://www.megasquirt.info/
  9. Sites

    Sites Member

    Joined:
    Mar 16, 2002
    Location:
    San Diego
    If I had the time, I would have probably done something similar. I ended up purchasing the Holley COmmander 950 EFI system that Jeff recommended and its currently sitting in my garage waiting for the motor to be built. Engine is currently torn down to the block and heads and I'm just waiting until the weekend to have someone help me pull it and get it on to the engine stand.

  10. ironbenderii

    ironbenderii Member

    Joined:
    Dec 6, 2003
    Location:
    Elk Grove, CA
    Your factory fuel system will do fine if you convert it over to mass air (fairly well documented exercise). Go for an A9L computer and some 24# or 30# injectors and you'll be in good shape...

    Cheap stroker kits, can't help you there. I had my short block (and my buddy had one for his class 3) built by D & D Motorsports in So-Cal. Great motor w/ crazy power!

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