With the LS engine rage taking over some of the Ford faithful, we are here to tell you there's another option—one with a Blue Oval still intact. Consider it therapy to counter the crazy idea that you have to run a modern-day, distributorless, fuel-injected powerplant to make horsepower. Although, it may take some additional science and thought from a builder's standpoint; with the right parts, tools, equipment, and know-how, you can really make a Cleveland rock.
Finding the right engine builder is essential in achieving the goals you have for your engine project. Whether it's high horsepower, longevity, or both, matching the right internal parts with the correct external ones is critical. John Bouchard, owner of John Bouchard Engines in middle Tennessee, is quickly growing a reputation for building strong, dependable engines that match the goals of his customers. Recently, one of his engines finished second in the 2015 King of the Hammers, a grueling, wide-open desert race combined with rockcrawling and trail challenges. This is a very impressive feat when considering the extreme environment and demands placed on the drivers and equipment. In fact, out of 132 entries, only 17 made it to the finish.
The idea for this Cleveland test came from one of his customers. It seems they wanted to see what a well-built, "hard-headed" 351 could achieve at the hands of a talented builder. So Bouchard, being a "hard-headed" Marine who's always ready to accept a challenge, agreed. "I'm always looking to prove that what ‘the experts' say can't be done, can be when combined with enough talent and creativity," John says.
Read along as we first test our little dynamo topped with a Trick Flow carb and intake, 2-bbl, open-chamber heads. And then we'll throw on a set of Trick Flow aluminum cylinder heads right out of the box and really test its full potential.
Here are the parts we'll be testing today. Trick Flow's CNC-ported 225 heads for 351 C engines come with 60cc combustion chambers, 2.08-inch intake and 1.60-inch exhaust valves, dual springs that accommodate a roller cam with max lift of 0.650 inch, and titanium retainers. The D-shaped exhaust port is raised relative to the stock design, so specific headers may be needed, depending on which car you drop this engine into. We paired the heads with Trick Flow's single-plane intake manifold and 650-cfm carburetors. Developed in partnership with Quick Fuel Technology, its new line of carburetors are outfitted with an electric choke and mechanical secondaries. Trick Flow's cast-aluminum valve covers are tall enough to accommodate screw-in studs and 1.73:1 roller rocker arms. We had to drill the plugs out to fit grommets for push-in breathers. The camshaft we used throughout the test was Trick Flow's hydraulic roller grind with 242 degrees duration at 0.050-inch tappet lift, 0.612-inch valve lift, and a 110-degree lobe separation angle.
We wanted to establish baseline numbers for our tests, so we ran the engine with a pair of OE cast-iron, 2-bbl, open-chamber heads with aftermarket valvetrain, but retaining the stock valve sizes. The heads were milled to give us a 9.3:1 compression ratio, and ignition timing for this and all future pulls will be set at 36 degrees total.
We were impressed with the initial numbers of 497 hp at 6,500 rpm and 448 lb-ft toque at 4,600 rpm. .
Initially, we were told this combo needed a 750-cfm carburetor, but Bouchard believed that the smaller 650-cfm would be a better match. He ran both to see who was right.
Aside from the cfm rating, the biggest difference between these two carburetors is the electric choke and choke horn on top.
The first pull with the 750-cfm carburetor showed that the fuel mixture was too rich. We decided to reduce the jets on all four corners. After removing the bowl, we found 74 jets up front and 84s in back. Those are too much for our little 351. We dropped four jet sizes all the way around and buttoned it back up for another pull.
After the jet changes, the engine made 501.8 hp at 6,400 rpm and 449 lb-ft at 4,600 rpm. That's not a huge difference in power, and because this is going into a street car, Bouchard stands by his belief that the 650-cfm carb is what works best on this iron head combo.
Comparing the stock 2V heads with the new castings from Trick Flow, it's apparent that Trick Flow redesigned the chambers for a better quench and more efficient combustion with them installed. With the new head, we'll still be street-friendly with a 10.75:1 compression—very streetable and still able to run pump gas.
Bouchard torqued the heads in a stepped sequence from the middle of the cylinder head out. Initially, the head bolts are torqued to 50 lb-ft and then 75 lb-ft, then one final pass to 100 lb-ft.
The exhaust rocker studs are in blind holes, but the intake studs pass through the intake runner, so sealant is needed to prevent any leaks. Bouchard uses a screwdriver to hold pressure against the guideplate, which will keep it from moving while being torqued down. Failure to do this will cause excess wear and premature fatigue on valvetrain parts.
After double-checking piston-to-valve clearance and pushrod geometry, we confirmed that the same pushrods and rocker arms could be reused with the new combo. This is critical when doing a head swap because different castings can place the valves in slightly different positions. Factors like thicker deck surfaces will affect valvetrain geometry. Don't assume all the parts are interchangeable.
A healthy coating of Comp Cams valvetrain lube will keep the springs lubricated on initial start-up.
Bouchard set the lash to the same setting as with the stock cylinder heads: half-turn past zero lash.
A bead of silicone is put down in prep for the intake. When done correctly, it should resemble a large welding bead in order to prevent the silicone from pushing out when tightening the intake bolts.
After a thorough cleaning, the intake from the original combo is reinstalled.
Bouchard tops off the new combination with the 750-cfm carb. The larger, re-jetted carb should be a perfect match for the increased air we expect these heads to provide.
Right away, this combo netted 562 hp at 6,500 rpm and 468 lb-ft at 5,000 rpm. The increase in compression and improved chamber design of the Trick Flow heads made a dramatic improvement in the power output.
We noticed the combo still wasn't pulling the full 750 cfm through the carb, so we tried a 1-inch spacer to help increase the speed of air to feed the hungry Trick Flow heads. The Trick Flow 750-cfm carb was installed on top of the spacer with no changes to jetting or timing from the previous runs.
With the spacer, we netted 573 hp at 6,500 rpm and 478 lb-ft at 5,000 rpm. The spacer cleans up the power curve at the bottom end quite a bit, but looks like it still wants to pull more at the top end. Since this is a customer's engine, we left it there, happy with the performance: 1.63 hp per cubic inch on pump gas and a hydraulic roller is respectable, to put it mildly.
This proves that what you've heard about Cleveland heads is true. Even a 2-bbl, open-chamber head can make upward of 500 hp with the right combination. Adding a set of Trick Flow heads right out of the box can really ratchet up the performance. You can either keep your dyno sheet for proof or just show them your taillights.
Parts List DescriptionPNSourcePrice 60 650 lift 60cc cylinder HeadsTFS-5161T003-C01Trick Flow$1,240 Dowel pinsTFS-51400420Trick Flow12.97 Valve coversTFS-51611802Trick Flow149.97 Intake gasketTFS-51600921Trick Flow19.99 Rocker armsTFS-53400621Trick Flow319.97 Intake manifoldTFS-51600111Trick Flow399.97 650 carbTFS-20650Trick Flow548.33 750 carbTFS-20750RTrick Flow707.61 Intake manifold boltsARP-154-2004Trick Flow31.08 Head gasketsfel-1013Fel Pro33.97 Head boltsARP-154-3604ARP91.2 Spark plugs3924Auto Light2.99 ea Camshaft hyd. roller 32-651-8Comp274.97 Camshaft thrust plate3122TBComp105.97 Hyd. retro fit lifters8931-16Comp540.97 Timing chain set (double roller)3121Comp66.97 Harmonic balancerM-6316-C351Ford Racing288.97 Distributor hold-down clampM-12270-A302Ford Racing7.97 Distributor (billet)MSD-8577MSD289.95 Bronze gearMSD-8581MSD48.95 Plug wiresMSD-31183MSD91.95
