by Jon Mikelonis

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.

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.

(Installation and "After" Testing)
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