Richard Holdener
November 1, 2009
Is the 400M a real contender? All it takes is the right bolt-ons and you have the makings of a serious stroker Cleveland.

If we were to query a group of Ford enthusiasts-not just the late-model crowd-about the performance potential and popularity of the 351 Cleveland, we'd be overwhelmed by stories and historical events that helped shape Ford performance.

Though short-lived, the Cleveland engine family was successful in nearly every form of motorsports, from NASCAR to Pro Stock, to say nothing of a serious presence on the street. And let's not forget the success of the Cleveland-headed Boss 302 in Trans Am racing.

Ask the very same group of enthusiasts about the 400M and chances are you'll hear nothing but crickets. If you do hear anything, it will be disgruntled rumblings about low-compression smog motors and engines suited for nothing more than towing-and did someone say boat anchor?

Like most performance build ups, the 400M came from humble beginnings, meaning it was wasting away in a nearby wrecking yard. Used basically as a rebuildable core, this motor was actually a runner (after replacing one bent pushrod).

This dichotomy seems odd, since the 400M is really nothing more than a large-displacement 351 Cleveland in disguise.Admittedly, MM&FF has not done much with the Cleveland series engine, mainly because there was so much to talk about with the 302 and 351W, and of course the wonderful world of modular engines. But with a great head design and 351 or 400 ci (not to mention a big surplus of parts), it's time to explore how much power we could make.

Maybe the trick is to ask our Cleveland enthusiasts about an aluminum-headed, tall-deck, stroker Cleveland? Misrepresentation of the much-maligned "M" you say? Read on.

The fact-checkers among you may point out that the low-compression smog motor is an accurate description of the 400M. "Boat anchor" may be a tad harsh, but it is true that the 400M was primarily used in full-sized vehicles and truck applications where torque was the primary concern. It is also true that in 1977, the 400M offered a mind-blowing 173 hp at 3,600 rpm and peak torque production of 326 lb-ft at a diesel-like 2,000 rpm

Thanks to Demon Engines and L&R Automotive, the two-bolt block was bored 0.030 over and stuffed with the stock crank (previously turned 0.010/0.010) and factory connecting rods. The stock forged rods received ARP rod bolts to ensure strength for those 6,500-rpm blasts.

Given a production range from 1971 to 1980, combined with a static compression of 8.4:1 (9.0:1 in 1971), the 400M was indeed a low-compression, smog motor. Oddly enough, it is this lack of desirability that makes it such a desirable commodity. Confused? The lack of interest by Ford fans means there are usually plenty to be found in wrecking yards, though it is getting tougher and tougher to find vehicles of this vintage. We've found complete (running) 400M motors for as little as $120!

Once you have a complete (and hopefully running) motor, the level of power you require will dictate how far you dig into the motor. The short and sweet route is to replace the factory two-barrel carb and intake with a four-barrel equivalent (from Edelbrock or Weiand), add a set of tubular headers (for your chassis) and possibly a mild RV-type cam (any cam ground for the Cleveland family will fit the 400M). If everything else is in working order, you can expect a solid power gain from these minor mods.

Taking things a little farther, you can step up in cam profile (to something just over 220 degrees of duration at 0.050) and perform a little port work to the 400M two-barrel (2V) heads. Combine the cam swap with a slight milling to increase the static compression ratio above that normally associated with forced induction use, and you can expect to literally double the original factory power output.

Expect torque production to easily exceed 425 lb-ft using a dual-plane intake and mildly ported two-barrel heads. If you happen to have a set of four-barrel (4V) heads, especially the more desirable early quench heads at your disposal (they are difficult to come by), they will really wake up a 400M thanks to a combination of additional airflow and static compression, though intake choices for the bigger four-barrel ports are all but nonexistent (more on the cure later).