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Introduction
There's no doubt about it, 351M motors in stock form are a total drag.
Fortunately, both internet folklore and 70's era F-Series and Bronco
enthusiasts indicate that outside of a total rebuild and upgrade to a Ford 400, a simple cam swap is a low buck mod anyone can take to poke these motors into action. So that's just what we'll be doing in this article
along with open-road test results to validate or disprove this common
351M shadetree upgrade.

Off-the-shelf flat tappet grinds are plentiful for 351M/400 motors, but
rather than going off the board with a unique pick, we went with a tried-and-true standard in the Edelbrock 2172 camshaft and lifter kit. In addition to the kit, it's mandatory to get the matching timing chain set that "re-indexes" the 2172 cam into its natural straight-up position. While we do not know the specs of a factory 351M cam, the primary culprit for this motor's poor reputation is due to the production timing chain and its 8 degree retard. A fresh set of matching valve springs is also recommended by Edelbrock, but for the sake of a trouble-free break-in, we left the old set in to avoid a wiped lobe. More on the springs later.

What are We Working With?
For those of you not familiar with FordMuscle's Project Redneck, the
1978 F250 is still running its original 75,000 mile 351M with modest
upgrades including an Edelbrock Performer Intake, Holley 470 Truck Avenger Carb, Hooker Headers, FlowMaster U-fit Dual Exhaust with 70 series mufflers, and a Mallory HyFire ignition. Despite the free breathing upgrades, other than better drivability over stock, most were moot due to
the impotent factory cam and timing chain set. Oil pressure is always an
issue with high mileage 351M motors and ours is no different. At idle the
M motor is pumping about 10 psi and when warm at freeway speeds, this old V8 is showing no more than 35 psi. Regardless, we've heard worse from other Cleveland owners, so we forged ahead with the cam swap despite an urge to yank the whole motor.

Baseline Tests: 0-60 Runs
It may not offer lush landscapes, but Northern Nevada offers plenty of
safe areas for open road testing. Before we got started on our cam swap, it was time to get a baseline in the heavyweight F250. We used an Autometer Cobalt D-Pic (aka g-force gauge) to record 0-60 times until we were sure the results were both consistent and optimum. We felt a quarter mile test was not safe for any public road, so we stuck with the 0-60 feature on the D-Pic. It took us six runs confirm the baseline results. See 0-60 times in the table below.

The intelligence of the D-Pic "G Meter" is all held inside the small
2-1/16" case. Connect the D-Pic to 12V key-on and you're ready to record
0-60, 60-0, and quarter mile times. Yes, that's it. Don't bother trying to
figure out how it works, it just does. Admittedly, during the first few
runs, it was bewildering to see the meter displaying acceleration in
perfect sync with the mechanical factory speedometer.


We "staged" the F250 and rolled out in 2nd gear. The New Process 4-speed is equipped with a granny gear so we skipped 1st gear.
 
Using the Autometer D-Pic was easy. We simply remained stationery, chose our 0-60 mode, ,hit calibrate, and waited for the "GO" indicator.
     

Once the meter senses the slightest forward motion in the 0-60 mode, the timer starts... so get on it!
 
Here's a short video showing one of our baseline 0-60 runs.


1978 F250 351M 0-60 Testing: Baseline
Run
Time
1
14.30 seconds
2
13.85 seconds
3
12.80 seconds
4
12.25 seconds
5
12.90 seconds
6
13.60 seconds

Camshaft Installation and Break-in
With the baseline results in the can, we got started with the swap.
Fortunately, being an ex-fire service truck, the F250 was mostly grime
free. This made the swap tolerable and fairly quick. We summoned the help of FordMuscle friend Rufus Crow, to help with the swap. These project ALWAYS go better when there is another person involved, especially a friend that needs no direction around an old Ford V8.


Rufus got busy knockin off the water pump with a ball peen and tire chock.
 
That's me, pulling the intake.
     

With the timing chain cover removed, we learned this was more than just an upgrade... it was mandatory surgery. In a way, it really justified the upgrade.
 
Further inspection of the timing chain made us grateful that the 351M held together during the baseline 0-60 runs.

 

In This Article...
FordMuscle takes a cam swap to the test in Project Redneck, our 1978 F250. Before and After 0-60 runs show you what the Edelbrock Performer Plus Camshaft and Lifter Kit will do for a 75,000 mile original 351M motor.

Edelbrock Performer Plus Camshaft and Lifter Kit for
Ford 351M-400 PN 2172
We selected the Performer Plus cam for our Project RedNeck because it offered a decent step-up from the stock cam. With low 200's duration and over .500" lift we'd retain good off-idle throttle response and maximize torque for this heavy four-wheel drive truck.

Cam Card
RPM Range 1500-5500
Duration .050" 204 Intake
214 Exhaust
Lift .484" Intake
.510" Exhaust
Lobe Separation 112 Degrees
Intake Centerline 107 Degrees


Find out more at Edelbrock:
www.edelbrock.com


 

 

Installation (continued)


The cam came out, but it was tight through the last journal. Some light revealed all 360 degrees of each cam bearing was intact. As for the
bearing surfaces? Who knows, we proceeded anyway.
 
Here's Rufus making sure the timing chain cover was going back on with perfectly clean mating surfaces.
     

Properly lubed, the Edelbrock 2172 was installed.
 
Now that's a nice looking timing chain. We indexed it dot-over-dot...
     

... but we still verified intake centerline with a degree wheel and a dial indicator. Dot-over-dot on this timing chain set yielded a 107 degree
intake centerline as specified on Edelbrock's cam card.
 
We tried out this new RTV with an integrated dispenser, it sure beats the
foil style and it never clogged or hardened in the tube. As always, no end seals for the intake manifold, just a heavy dose of RTV.
     

Torquing down the intake in sequence.
 
Some new Edelbrock Cleveland-style valve covers.
     

After adding some straight 30 weight and a new filter, we used Comp Cams break in lube to prevent wiping a lobe. It's always tense breaking in a cam. 20-25 minutes at 2000-2500 RPM. Afterwards, the F250 settled down to a nice idle.
 
With the cam broken-in and the motor cooled, we drained the oil an added a fresh Ford Motorsport filter and 6 quarts of Rotella T.


 
Here's a short video showing one of our "After Cam Swap" 0-60 runs.

After Test: 0-60 Runs
We wasted no time and headed out immediately for more 0-60 testing. The truck was noticeably up on power during the 15 mile run to our secret spot in Mustang, Nevada. This time we just performed 3 runs before noticing the clutch heating up. However, we were able to tick off an 11.5 second 0-60 time on the third run.

 


1978 F250 351M 0-60 Testing: After Cam Swap
Run
Time
1
12.95 seconds
2
11.80 seconds
3
11.45 seconds
4
13.85 seconds
5
13.65 seconds

Conclusion
Satisfied with the improved 0-60 time, we enjoyed the ride back contemplating the next motor upgrade for Project Redneck. A logical step would be to have the heads rebuilt and to complement the cam with the matching Edelbrock valve springs. However, with 30-35 psi at freeway speeds and waning, we knew the effort and investment might be pointless on the stubborn 351M. Reality check... run it until it dies and save some coin for a TMeyer Inc. 400 with Aussie heads. Another day.


Posted by retyler, 06/14/09 05:33pm:
Very interesting. Articles like this one makes Ford Muscle very worth while. It would also be interesting what one could actually wring out of one of these M's with all the right parts.
Posted by LXguy, 09/15/09 10:37am:
Gotta love old Ford trucks. You guys out west have it lucky. Every one of those around here its rusted away to nothing.
Posted by 77Thunderbird, 10/21/09 07:10am:
Well fellas if your wanting to see what a 351M is capable of. Ill show you, ive got a 77 T-bird with a brand new re-maned engine. It weighs 5900 lbs and im not gonna put her on a diet. 351M, EB performer intake, EB 750 4bbl, Comp Cam @270H grind (from about 248 stock), CC springs, CC pushrods, CC lifters, Malory 80gph fuel pump, Summit full length headers, and HEI distributor. I'm in Iraq right now, but Feb. 09', Shes Finished. So I'll put a video of 0-60 & QM times just for you guys.
Posted by docride, 02/21/10 01:29pm:
Great to see this article,takes the mystery or should I say misery out of my 351M up grade




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