I have an 1981 F100, with an I6. It's been rebuilt, also new carb, distributor, plugs wires, etc, flywheel. After $1500 it still runs like sh@#. I've taken it to 2 different Ford Shops, 2 different mechanics and noone can get it to run right. I have to set the idle up just to keep it running and from stalling out all the time, and it idles rough.

Anway,, I've been thinking of putting in a 351 windsor. I've been told it's fairly simple since there is no EFI, and the C6 tranny will bolt up to it. The main mods are the mounts, radiator, flywheel so I've been told. Any advice, add ons, what I need, what problems I'll have, or if anyone has step by step instructions that would be great.haha
My dad is actually a mechanic and he offered to help me do it, so were going to tackle it. Just wanted to ask guys who've already done it, what to expect and parts to buy.
Thanks

Josh

 

you're gonna have to change the rad as well



Jim

 

throttle cable may be of different length. "mounts" would also equal frame mounts. Use a duraspark II ignition, which may be your problem already. early 80's they started to try different ignition setups, but the duraspark II is still best. Make sure you use the 351W flywheel.

 

If you decide to get a new distributor, consider our custom curved Duraspark Distributor built with our new Full Length Oil Impregnated Bronze Bushing. The full length bushing improves timing stability and spark scatter. If stock appearance is not an issue, take a look at our one piece D.U.I. Distributor. Whether you choose the Duraspark or the D.U.I., we curve each on a distributor machine based on your engine combination. Please see them at:


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Also, there is now an excellent installation article on the D.U.I. Distributor on the Ford-Trucks.com site at:

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https://www.ford-trucks.com/article/idx/0/358/article/DUI_Ignition_Installation_In_A_Ford_351W_V8.html

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A lot of work, time, and money just to replace an engine that won't "run right" I think. But anyway.. the best way to do this would be to score a wrecked 351W truck or Bronco and just swap everything. I've never been so lucky.
You have to change the "engine stands" that go from the mounts to the frame. These are riveted and bolted to the frame. You can drill these out (hard) and simply replace them with 3/4" bolts. The entire front 1/2 (at least) of the exhaust will have to be replaced. You'll need a matched set of power steering, AC, and alternator brackets specific to a 351W ONLY. Also the pulleys, all 351W pulleys are NOT the same and are hard to mix and match. The distributor, intake, oil pan, and exhaust manifolds are also 351 specific. Hopefully your donor engine is complete as as possible. The oil pan has to be a "truck", not a car pan. V8's run hotter than I6's so even if you cobbled a set of hoses up to work the radiator would be insufficient. A 302/351 fan shroud and fan. Radiator hoses and no doubt stuff I'm forgetting.
The C6 is fine with the appropriate 302/351 flywheel. Wires all should reach ans even be too long except maybe the distributor wires. Only a couple of those, easily extended. Simplified if you use a Duraspark II setup, almost any V8 car or truck can donate that harness or it can be made. Alternator works, if you have the 351 brackets. The power steering pump will swap but you need to use the specail puller to get the pulley off, remove the bracket, bolt on the 351 bracket, and then the installer tool to put a pulley back on. No way around the special pulley tools unless you score a 351 pump and bracket together. The gas cable will work though you have to put a big loop in it which will look dumb (how do I know that?). A 302 cable is a tad too short, and a 351W just right. Took me quite a while to find a good used one.
You are aware that 1988 and later 351W's are EFI? You can still swap one but it gets even more complicated.

 

Buy another 300 I6 with EFI. Drop it in.




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I'm only semi-joking.