I've actually got a 351w in my boat and have been looking to do a basic tune up on it. It's an 86 model boat and has a 4BBL carb on it. The previous owner said he did something with the ignition but I can't remember what he did. I've tried the older model distributor caps from the 70's model 351's and they are a little too large and the rotor just spins in place. The distributor caps from the 80's model 351's are massively different.

Does anyone know of a distributor upgrade on these engines?

Here are some pictures of the engine. Obviously, it needs some cleaning up and I'm working on that. I'm 99% sure it's a 351w and the new valve covers I bought look like they'll fit but I haven't bolted them up yet.

 

Unfortunately your pictures don't show the distributor and cap very well. Try to get pictures of just these parts.

"...distributor caps from the 70's model 351's and they are a little too large and the rotor just spins in place."

The distributor cap does not keep the rotor from spinning, that is done by the distributor upper shaft that has a cutout to engage a molded in tab in the rotor. So it sounds like you have the wrong rotor.

Ignoring the rotor, does the replacement distributor cap fit properly?

A good parts store should be able to match up new parts if you bring in the old samples. Old parts men will often recognize these parts with a good look.

Does this distributor use points?

 

Yeah sorry. I was really just posting pictures in regards to the engine block itself. The base of the old distributor cap will fit inside the base of the new one so it's much too large. You're right, the rotor is what's actually spinning on the distributor shaft. Sorry if that was confusing. My distributor shaft is almost a half moon shape and the new one was circular with a slight notch at the top. This system doesn't appear to have points as I don't recall seeing the condenser, points, etc. but it still has a moving rotor so an electric system doesn't seem right either.

I have the distributor cap and rotor with me and I plan to take them into the auto store today but was hoping for some knowledge to help them out.

 

Ok so I was able to determine that the ignition is a no points. It's a Pertronix 1581-82. However, the kit only comes with the rotor and ignition kit. There is no distributor cap as far as I can tell. I also had the guy at the parts store looking into it and he tried every engine we could think of with every VIN number at roughly every 5 years in succession. Multiple vehicles were also tried. We pulled 3-4 different distributor caps and none of them were the same.

 

Try to find a Ford number on the distributor body, or other markings to verify either that it's a Ford unit or other.

From that number it may be possible to determine more about the distributor and thus the cap required.

 

I did check into that yesterday. Unfortunately, the only thing written on the distributor is a plate on either side that's rivetted on. The plate reads Marine SAE-J1171 which appears to just be a comformance spec for electrical equipment. I'm getting really close to just running this one for another year or two and buying a new distributor.

 

I'm willing to bet that is a marine specific distributor you have there so you're probably wasting your time looking for it at an automotive parts store.. you'll have to go visit a marine shop.

 

I can't be too sure from these fine pics, but that kinda looks like a mallory distributor