After much consideration, I've decided that the best engine for my winter project is a 347, but it's hard to get a good fix on how to screw a 347 together for a truck. Most builders are wanting to use them to push a Mustang down the 1320 in a ridiculously short period of time and the slant of much of the info I've found reflects that. Given the similar bore, stroke, and engine design of a 347 and a 351W, I've taken most of my cues from the folks with a 351W in a truck. I'm attempting to accomplish two things here: build an engine that is well-suited to my needs and plans for the truck and get it done with as many of the leftover parts as possible that I already have on hand. For this reason, this combo might not be absolutely optimal, but I've been doing some research and I think it's pretty close. Give it a look and see if I'm overlooking something obvious that will give me grief.


- Probe stroker kit with the 5.315" rods and 20.1cc reverse dome pistons. Should yield right at 9:1 static with the rest of the combo.
- stock 5.0L block other than .030 overbore, milled for zero deck, and clearanced for the longer stroke
- stock unmolested and extremely low mileage Explorer GT40P's
- '90 5.0L HO cam advanced 2* and 1.7:1 rockers. The Lightning guys seem to like this setup with the 351W. Results should be similar here.
- 5.0L truck EFI intakes and stock throttle body w/19 lb. injectors. Truck 5.0L intake is apparently a little much for the 5.0L, but should be about right for a 347.
- Coated shorty block hugger headers. These are necessary to fit the chassis.
- speed density ECM and harness out of a 351W truck.


The truck is a 3/4 ton 4x4. It'll probably end up with a 31 - 33 inch tire max. ZF 5-speed and 3.73's. It'll be a general purpose pickup with fairly frequent trailer duty. 4750 RPM max and that would be a rare occasion. No racing, hardcore off-roading, or other stupidity. I want excellent low-mid range torque and good fuel economy. The goal there is 15 MPG. I've crunched the numbers and I think this pile of junk might just get the job done. In fact, I think it'll be a brawnier and more efficient powerplant than a 351W. The only things I don't have here already are the headers and the stroker kit, so it will be an inexpensive build as well. Thoughts?

 

Seems like a good plan, let's wait for the results, i'm very interested . I'm wondering how that 351 ECU will work for you.

 

Thanks for the input. I'm a bit anxious to see how the 351W ECM handles it also. The 5.0L HO cam uses the 351W firing order and with only 4 less cubes, I wouldn't think that the ECM would even know the difference. I'm not against swapping to mass air if there is an issue, but I'm really hoping this works as-is because I already own the ECM and supporting parts. I guess I'm going to find out!

 

good luck sounds like you have a good plan and low CR so maybe next time you come in to money it could see a blower!?!? that would put most 351w in the rear view

 

Sounds good to me.

 

Thanks for the replies. It sounds like I've got a good plan. I'm selling another engine to a buddy for his Bronco. As soon as I get it put in and get paid for it, I'll be ordering the stroker kit and getting the block machined. I'll report back with the results in a couple months after I've got it running.

 

By no means should anyone take anything I say as a criticism, but I have a question or two.

Why go with a 347 and the added expense of the stroker kit? A 347 is 4.030" bore X 3.40" stroke, correct?

A stock 351W is 4.000" bore X 3.50" stroke without all the complications.

Usually, as far as I've ever heard, you do up a 347 so that you have a low deck height. Being that this engine is going into a truck that's not a concern.

Of course, you are allowed to do whatever you want, I'm just curious why the bother?

 

That's a good question. I actually do have a low mileage remanufactured 351W sitting here that I had planned to use in this truck. There are several things that made me change my mind, but most of them were due to logistical problems with fitting the 351W into this particular chassis equipped the way I want it. The truck is a '52 and the chassis and engine bay are much smaller than any Ford truck built in the last 45 years or so. The 351 itself would have fit, but the combination of the accessory drive system that I need to use to work with some of the other mods to the truck was giving me grief and so was the exhaust. The tighter 302 package allows me to use the accessory drive I need to use without any chassis or inner fender interference. The headers would have had to be purchased plain, modified, and then sent back out to be coated with the 351W while they fit fine as-is with a 302-based package. That will save me money and allow me to run off the shelf coated headers. The 351W is a flat tappet block and doesn't have a cam in it, so I would have had to spend $300 on a cam, lifters, and pushrods to complete it whereas I already have a decent cam and valvetrain for a 302-based engine and it's a roller setup to boot. The truck 302 EFI intake actually has much bigger ports and is better suited to a big inch small block than the dinky ports on the 351W truck EFI intake. Less weight figures in here also. Less HP loss and better fuel economy from smaller journals in the bottom end and less rotating mass were also factors. The plus column just kept stacking up in favor of the 347.

The last straw was the fact that my buddy's Bronco sneezed it's motor and he's found himself in need of a good 351W. Between what he agreed to give me for the 351 I had and the money I'll save by not having to mod the headers and buy a valvetrain, the stroker kit will be basically free. The only extra I'll have to pay for is getting the 302 block machined. I love the 351W and I think it's a great engine for just about any Ford truck, but in my case with this particular truck, the 347 will just be a better overall fit.

 

Oh duh, sorry, I assumed you were talking about a truck that came with a small-block stock. Which would mean a 1960's and later, which would have had plenty of room.

Sounds like a good plan

 

Blue Oval, it looks like you have it thought out well and I agree with your reasoning.
Go with the 347, help your buddy with the 351W and good luck on your project. It
sound great.