Mark Houlahan
Brand Manager, Mustang Monthly
April 26, 2012

Shortly after the earth cooled, modern man started modifying Flathead V-8 engines with upgraded cylinder heads, intakes, and camshafts. Famous names we know of today, such as Edelbrock, Offenhauser, Isky, Manley, Crane, and dozens of others can trace their beginnings back to offering speed parts for the Flathead. It was known in all the speed circles that you could easily double your Flathead's power output with a good set of heads, a new intake with a couple of Strombergs, and of course, a camshaft from one of the greats like Harvey Crane, Ed Iskendarian, Clay Smith, or Ed Winfield. So it went, throughout the history of the muscle car era; upgrading your heads, cam, and intake/induction was an easy recipe for power.

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Today, a lot has changed with the internal combustion engine. Direct injection, multiple runner EFI, factory turbo or supercharging, and so forth often make the traditional heads/cam/intake swap difficult, if not impossible for the home wrench spinner to accomplish. Sure, Ford's modular engines have cylinder head, cam, and induction offerings (we hope to upgrade our 4.6L Three-Valve in Generation Gap some day with such parts), but the overhead cam design means special tools, manuals, and more to get the job done. So it's nice when you open the hood of your classic Ford and still see a traditional small-block between the shock towers sometimes. With our '70 Mustang High School Hauler project, of which we desperately wanted to increase the 302's output, we had giddy thoughts of the proven and timeless heads/cam/intake swap for months now.

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The great thing about performing this revered hardware upgrade is that as long as you stay within the parameters of the parts you're bolting on, it's just that, a bolt-on upgrade. Many of the manufacturers out there have built and tested these parts in similar combinations, so you know going in that purchasing head A, with camshaft B, and pushrod length C that everything will work in concert. In today's sales speak, this is often referred to as a "top end" kit or "power pack," or something of that nature. Besides a crankshaft damper puller tool, the rest of the swap can be accomplished with a standard mechanic's set of tools you already have in your garage, making the swap that much more palatable for you weekend wrench benders.

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Knowing that to upgrade our heads/cam/intake, we'd also be shopping for gaskets, and a few valvetrain parts (the famous "while we're in there" upgrades like roller rockers, and so on), we picked up the speed parts bible, aka the Summit Racing catalog, and started flipping pages. Yes, we still like a printed catalog to thumb through, but even after checking out Summit's detailed website, we couldn't find a complete combo package for small-block carbureted Fords. Sure, it had Summit Top End Pro Packs for Brand X and great packages for EFI small-blocks, but not for those of us still using a four-hole fueler. Fear not, though, as a quick call to Summit's tech line allowed us to put together all the right parts in a custom package. Essentially, we used Summit's TFS-K514-350370B Trick Flow 350 HP Twisted Wedge Top-End Engine Kit, and substituted one of Summit's carb and intake combo kits for the EFI manifold (see Shopping List sidebar for all the parts details). Needless to say, Summit made it easy and we had everything ordered and delivered in two days. It's time to get to work and make some horsepower!

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Shopping List

After discussing what we wanted to do to our Mustang, Summit Racing suggested the following for our build. Feel free to use these suggested parts in your small-block build, or adjust as your budget and power level requires.

PartPart NumberPrice
Trick Flow Twisted Wedge Cylinder HeadsTFS-51400004$1,299.95
Trick Flow Stage 1 Roller CamTFS-51402000$179.95
Trick Flow 1.6:1 Stud Mount Roller RockersTFS-51400510$269.95
Trick Flow Billet Steel Timing Chain SetTFS-51478520$70.99
Trick Flow Head Bolt KitTFS-92005$39.95
Trick Flow Hardened Chromemoly Push RodsTFS-21406700$99.95
Trick Flow Hydraulic Roller Retrofit LiftersTFS-21400006$429.95
Trick Flow Black Valve CoversTFS-51411801$109.95
Trick Flow Head Gasket KitTFS-51400904$94.95
Fel-Pro Timing Cover Gasket SetFEL-TCS45008$14.95
Fel-Pro Oil Pan Gasket FEL-1809FEL-1809$14.25
Summit Racing Carb and Intake ComboCMB-03-0211$464.69
Trick Flow Cylinder Head InsertsTFS-51400265$9.49 (x2)
Total$3,108.46

On the Dyno

After verifying our Pertronix billet distributor's gear was compatible with the Trick Flow roller cam, it was simply a matter of dropping the distributor back in with the rotor pointing at plug wire number one, wiring the plug wires to match the firing order, adding fresh coolant and priming the fuel system to start the '70. With the first twist of the key, the 302 shouted to life and maintained a nice high idle. A quick stab of the pedal pulled the choke off and we let the 302 warm up while timing was set to 10 degrees (initially) and we chased a small leak. With just enough miles on the new combo to make it to the gas station and back for some fresh 93 octane, we strapped our fresh ride to our in-house Dynojet chassis dyno to make a few pulls.

Right off the bat, we were impressed with the Summit carb and how dialed in it was from the factory. With air/fuel ratios in the 12.8 range during dyno pulls, we had nothing to worry about. The plugs looked great on inspection and all we ended up doing was pushing four more degrees of base timing in (for a total of 14) and raising the rev limiter on the Pertronix Ignitor III under the cap because we were actually tickling it during dyno pulls now that the engine could really breathe. When you check out the numbers, don't just fixate on the peak numbers, but look at how much was picked up under the curve as well as how flat the new torque curve looks. Where torque peaked around 3,000 rpm before, the new combination is just starting to pull. From 3,500 to just over 5,000 rpm, the torque curve is nice and flat and just keeps on going. On the horsepower front, we gained plenty with the upgrade. Horsepower is comparable down low, but where the old combination was over with around 4,300 rpm, the upgrades netted us more horsepower that just keeps climbing well past 5,000 rpm now. We've been able to maintain our low-rpm power and torque, while increasing the engine's power from 3,500 rpm and up nicely.

BaselineHeads/Cam/Induction
RPMHPTorqueHPTorque
2,900143.17259.28138.35250.56
3,000148.25259.55143.89251.91
3,100152.67258.66150.66255.25
3,200157.15257.93158.82260.66
3,300160.78255.89166.02264.22
3,400164.24253.71173.90268.63
3,500167.78251.76180.53270.89
3,600170.17248.26187.16273.05
3,700174.25247.35193.58274.78
3,800176.76244.31199.67275.98
3,900179.58241.84206.63278.27
4,000182.37239.46211.16277.26
4,100183.90235.58215.55276.12
4,200184.77231.05222.87278.70
4,300184.92225.86226.68276.88
4,400185.28221.16232.15277.11
4,500182.35212.83236.21275.69
4,600177.97203.20241.53275.77
4,700180.83202.07247.97277.09
4,800177.74194.48251.86275.59
4,900170.33182.58255.38273.73
5,000N/AN/A256.05268.97
5,100N/AN/A260.66268.44
5,200N/AN/A260.66269.24
5,300N/AN/A270.21267.77
5,400N/AN/A272.18264.72
5,500N/AN/A252.88241.51
5,600N/AN/A187.07175.45

Baseline: 182.37 hp at 4,000 rpm, 259.55 lb/ft of torque at 3,000 rpm
Upgrade: 272.18 hp at 5,400 rpm, 278.70 lb/ft of torque at 4,200 rpm
Peak Gains: 89.81 hp, 19.15 lb/ft of torque