I have a 1978 F150 that I bought from my grandfather when I turned 15 for a dollar, it was the first truck he ever bought brand new. I was able to hold on to it through college and a couple moves. Now that my wife and I are settled in I am looking at some ways I can start to have some fun with the truck. Its a 2wd Ford F150 Ranger lwb all original for the most part and I drive it about once a week. Im looking to make some upgrades in the engine department, it has a 351M in it. I dont have a pile of money laying around to rebuild it but would like to slowly change parts out and build it up. First on my list I think would be swapping out the old 2 barrel for 4 barrel. How much would this help the 351M. I understand the 351M is a smog engine and everybody says pull it out and put a Windsor in or make it a 400 and I don't have the money for that right now. I'm open to advice and if anybody has similar experience's. Replacing the engine will not be an options.
Thanks in advance for the responses and advice.

 

Pictures. We need to see pictures of that truck – the more the better. Words alone will not convey the holistic impressions FTE members need in order to relate to your truck and your situation.

 

That and we like pictures around here...

The 351M has some potential without converting to a 400, but as the old saying goes, "there is no replacement for displacement." I'm no expert on that series of engines, but there are several here that are and can provide much better advice than I. Most engines from that era ran with about 4 degrees retarded on cam timing and pretty low compression. Neither is terribly expensive to change.

 

Lots of potential there. You can put a Edelbrock Performer 400 intake manifold on it. There's tons of carbs to choose from and I'd stay below 600 cfm. This will get rid of all your smog horse crap. As Wyrm73 said, the camshaft is a little lacking. At the very least I would replace the timing set. A lesson I already knew, but still learned the hard way...twice.

Since you're going to have the intake off anyway, think about making it an all weekend project and replace intake, carb, and install a complete camshaft kit.

 

 

Nice!!

 

Agree that you can do stuff to the M engine to wake it right up. I'm not upset that people say get a Windsor. After all, it's a good family of engines and lasted probably longer in the Ford lineup than any other model that I can think of at least in modern times.
It's lighter than an M, has a bazillion supporters that make cool stuff for it, would likely power a truck like yours better than a stock original M motor would any day. And the Windsors were available in the 2wd truck right from the factory anyway, so it's not really out of character to put one under the hood.
Plus you could pull a fully fuel-injected engine out of a later truck and have quite the setup.

But I'm a fan of the M engines too. Nothing wrong with making them work better than they were able to when literally just learning to deal with lowering emissions. Look how far they've come from that learning curve though! You can get 500bhp engines in cars that have lower emissions than ever and still get 30mpg! Not that you're going to get that out of a truck chassic/body setup, but hey we can dream!

Are you going to do all the work yourself? Or have to farm some of it out?
How much do you know about engines and building them? Reason I ask is that along with the intake manifold and the timing chain, you are literally THIS close to being able to put a new cam in it too. And those three things, along with a good breathing exhaust should really wake it up. Enough to feel it by the seat of your pants. And the passengers would feel it too.
Not going to be a road burner without a lot of work perhaps, but a lot of that is in the cam choice anyway. New cylinder heads are typically at the top of the food chain when it comes to how much they cost. And the days of $100 cam and lifter kits are long gone, but you can get things rolling along for not too much. Depending on your family budget and if you've got kids too!

The thing I like about the intake too, is that you'll likely shave 25 lbs right off the top!
Headers are usually quoted as having a big effect all by themselves with most engines. Don't remember a lot of direct feedback here or on other sites for header users though. Be interested to hear what users say about their experiences though.
But a full exhaust system is a lot of money these days too, unless you do it yourself from clamp-together kits.

Anyway, I've been rambling since the "you can do it" part.
Just enjoy it and do the things mentioned. Timing chain and carburetor intake. Cam too if you can put it in the budget.

Paul

 

 

Heres a couple ore pictures. I plan on doing all the work myself, I know just enough about engines to get my self in trouble. But what better way to learn than just do it and learn as I go. I mean that's what youtubes for right.

 

First off, I would get rid of the stock timing set and get a straight up timing set for it, definite power & MPG improvement after I did that.

 

I like the short story and I really like the pictures. Sounds like you have a great base to start from for a truck.

I was told time and time again to swap the 400 in my truck for a 460.... but I like being different and enjoy paying less at the pump less often. But that's me. I say stick with your current motor - there's nothing wrong with it as long as it's running well (doesn't use oil, no blue smoke, no major leaks, etc).

If you're intending on using it sparingly (once a week) as you've already done, then there's plenty of things that can be changed on the truck to improve its 'fun' factor.
- Remove all the smog stuff. It makes the engine cleaner and easier to work on with less junk under the hood.
- Swap out the intake for a cheap (look local) 4 barrel. Edelbrock, Weiand and Offenhauser are your best options. You want a dual plane intake manifold, not a single plane.
- Throw a 4 barrel carb on top of the intake (holley, edelbrock, summit, whatever you can find for a decent price).
- Swap out the original timing chain for a new one (double roller is preferred, but is expensive) and set the timing 'straight up'.

With these small 'upgrades', you'll wake up that 351M, it'll be more fun to drive, and easier to work on. There's plenty more you could do, but you don't have to go to extremes if the budget doesn't allow it.

 

Aaron-71 nailed it on his recommendations. X2 on straight up time it. Meaning get a 70's to 71 timing set that is the easy 1st mod then yes on the rest.
T Meyer is the 351M guru.http://www.tmeyerinc.com/

351M sites that are helpful 351M/400 Performance Build Up

M-Block 351M/400 Performance

351/400m Power Kits Barnett High Performance

 

It's probably been talked about around here, but does everyone remember the old Hot Rod Magazine article they did on one of their shop trucks about 20 years ago or so?
They took the old tired (400 I think it was) engine, after dyno testing it first, then a quick-n-dirty basic rebuild and dyno'd it again. To put it mildly, everyone was shocked!

The chassis dyno was even at a tuner shop for Porsches or something like that, so everyone got a good laugh at Ford's expense when it showed a measely 100 hp or something crazy low like that.
The sports car guys were not laughing when the second dyno came in and showed like 240 hp and 450 lb ft of torque.
So don't hold me to those numbers, but it was a great little article.

The links in Rich's post look interesting. Should make some good reading. We had a good time over at ProjectBronco for a few years. Lots of good info flowed through there.

Paul

 

Here it is. How We Got Over 500hp from Ford's 400M Engine - Hot Rod Network

 

Those are the best articles for info on the M-blocks.

Then there's all of the info over on the 335 series forum with technical info, build information, dyno sheets/results, etc.

I based a lot of my build off of what others have done. I say don't reinvent the wheel if you don't have to. Here's one that was a huge inspiration for the way I chose my parts: https://www.ford-trucks.com/forums/1...ml#post9649662

smokeyb97 made a really decent amount of hp, but lots of torque, and torque down wayyyy low. 450+ ft-lb of torque at 2,600 rpm??? That's a holy-hell moment if you ask me. Particularly so when many have passed up on this motor or called it a 'boat anchor'.

But when you think about it, it makes sense. The 400 is the longest bore + stroke combination (from factory) that ford ever made.