Alright fellas, get ready for a long one. So, my 351m has a rod knock and I'm at a crossroads with what to do with it. The engine at the very least is going to need to get pulled, stripped, and hot tanked, and potentially, bored and honed. I'd like to make the truck more user friendly, as it was originally intended to be a daily driver, but it doesn't have the power I was always looking for, and the gas mileage is a joke.
Reliability is important and I keep hearing horror stories about the 351m as a platform; stories of guys rebuilding engines getting 30,000 miles out them, and then spinning a bearing again, having a piston ring go, etc. I'm open to the idea of throwing in a new engine, but I'm not sure what would be a good fit; I know I probably want something bigger than a 302, but I don't have any experience with Ford Crate motors (originally a vintage chevy guy). Any and all suggestions are welcome. Like I'm open to someone spitballing on how to throw an LS in there. What I'm looking for is power, torque, and reliability, for a relatively low price. I certainly don't want to spend the value of the truck on turning it into something worth driving.
Does anyone have any experience with MSD atomic EFI? The truck is a 4x4 with a manual 4 speed, and I don't want to do any welding, so keep that in mind with new motor mounts and all that jazz. Something that wants to just bolt in would be great. The idea behind the build is to be able to do it on my own/with a couple of guys at home. If the consensus is to keep the 351m and rebuild that, what are the smartest power upgrades?

 

I don't know why, but it's not letting me upload photos, so here's some google drive links. Hope that works

https://drive.google.com/file/d/0B-r...pmc3lRWUk/view
https://drive.google.com/file/d/0B-r...lUWklEX0k/view
https://drive.google.com/file/d/0B-r...pmc3lRWUk/view
https://drive.google.com/file/d/0B-r...5GSTZzSUE/view

 

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The 351M is a good motor with a bad rep mainly due to meeting new EPA requirements. The biggest mistake I have seen is using the wrong oil. These engines need zinc (ZDDP) in the oil to cushion the bearings, cam and lifters. Because of EPA regulations the timing is retarded and compression is low. With that said the 351M/400 breaths new life with a straight up timing sprocket and new pistons (See Tim Meyers website). Bolt on some headers, intake manifold and an appropriate sized carb and you will have a dependable well powered motor.

 

Make it a 400, alum intake and a good carb and X2 on straight up time it to wake it up.

Home work time.

T meyer can set you up. http://www.tmeyerinc.com/

M-Block 351M/400 Performance

High Performance Options for the 351M/400 Engine - Ford-Trucks.com

Building a Ford 351M, 400, or Cleveland Motor

I have more 351M links on the home computer.

 

The 351m will respond well to basic upgrades. A "straight up" timing set to correct the factory timing retard, small 4 bbl, dual exhaust and headers. A 400 will respond even better and has more aftermarket support.

Rebuilding it as a 400 would be my suggestion. More cubes, more power and lots more potential for upgrade. The crank and pistons are different vs 351m, all else is the same and it bolts right in.

How far you take the build depends on goals and budget. More compression will help. More compression and quench (ie. the flat on the piston comes within .040" of the flat on the head at TDC to control ping) with aftermarket heads will help even more... including (maybe even) fuel consumption.

 

More motor home work. lol

History of the Ford 351M

351M/400 Performance Build Up

Bubba's M-Block Ford V8 Workshop

Timing chain 101 w/pics. 351M/400/360/390/429/460 Timing Chain Replacement - Ford Truck Fanatics

And some thing cool to ck out. Rough Country Rustic Furniture & Decor - Flags

 

Okay, so lets talk reliability and cost. If I convert my 351m to a 400 is it going to
A) cost less than buying a 347 crate motor and churn out more power
B) be more reliable

 

Also, does anyone have any idea why my engine may have developed a rod knock? Assuming the previous seller was correct when he said "it had had an engine and tran rebuild 3000 miles ago." Assuming he's not lying, and I grant you, I haven't taken the timing chain and checked it for wear to see if they didn't just put a coat of paint on it to instead of actually rebuilding it, what are some reasons for it to develop a rod knock? My theory is that they either, didn't burp the cooling system properly, or the owner didn't hold off on beating on it until it was properly broken in.

 

There are many reasons as to why it has developed a rod knock, Improper break in, wrong viscosity oil, improper assembly procedures. To much bearing clearance. No/low oil pressure at first start.

 

I'd just go with a full re-build of the 351m with some upgrade parts. If you go for the 400 crank then get 400 heads with upgrade springs to support an RV camshaft. Dual plane aluminum intake, new four barrel carb and double-roller timing chain set straight-up. Get TMeyer pistons and the correct thermostat.

I'd pass on the headers, but install dual exhaust with glass packs

Disclosure: I installed Summit headers on my truck. I love the sound, but I don't think they really helped performance

 

So I know about the strait up timing sets that we all talk about. But can you still buy the original retarded sets.

 

From what I understand if you get a timing chain for a 78 351M and install it following the marks it will be the 8* retarded. So YES you can still buy a "retarded" set.

To get a "straight up" timing set you need to get a set for 71 (?), I am pretty sure it is discussed in the links I posted for you.

"Changing the timing chain makes a world of difference on the 351M. The stock chains are retarded timing wise 5 degree, and just get worse as they stretch. Get a 71' chain with no timing retard and they are completely different motor."

 

The Summit set can be set advanced, retarded or straight-up. As you like:

 

Rebuilding the 351 will be much easier. The 347 is based on the 302 block. It will not bolt up to your transmission.