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6 Small Block Ford Cylinder Heads That Work

Bolt-On Power For Less Than $1,350

By , Photography by

Ford Racing X307
The Ford Racing X307 head is not the casting that comes on the Boss 302 crate engine, but its affordable price made it a natural choice for this test. It's important to note that this was the only head in our test that required its own separate valvetrain. The Ford head uses a net lash design that makes the valvetrain non-adjustable. The Ford roller rockers use a fulcrum base and a 5⁄16-inch bolt to attach the rockers to the head. We used Comp roller rockers for the remaining heads to level the playing field, but if you are considering a set of these heads, be aware that the rockers and fulcrums need to be considered as well. The Ford heads did well during the testing, making a peak of 362 hp. Much of this gain over the stock 345 hp Boss 302 rating can be attributed to Westech's lower 140 degree engine coolant test procedure and open dyno headers. These Ford heads tied with the Edelbrock heads for Third Place in average torque and were extremely close to the RHS head's Second Place power level.

Ford Racing 178cc
PN M-6049-X307, $1,119.90

Peak HP 362
Peak TQ 346
Valve Sizes 1.94/1.54
Intake Port 178cc
Chamber 58cc
Valvesprings 1.500-inch Beehive


Speedway Motors/Flo-Tek
The most notable thing about the Flo-Tek heads available through Speedway Motors is the price—that's $739.98 for a complete, ready-to-bolt-on pair of aluminum heads for a small-block Ford. While the average power was down compared to the TFS, RHS, and Edelbrock heads, the power is still acceptable, especially if you are more interested in a nice pair of aluminum heads rather than ultimate power. Peak power was good at 349 hp and torque is also reasonable. These are certainly worthy of attention at this excellent price.

Flo-Tek 180cc, Speedway Motors
PN 7223000, $739.98

Peak HP 349
Peak TQ 347
Valve Sizes 1.94/1.60
Intake Port 180cc
Chamber 58cc
Valvesprings 1.250 single, max lift 0.550


Racing Head Service (RHS)
The RHS heads come out of the box with a very nice-looking casting that backs this image up with respectable performance. The heads offered an excellent midrange power curve behind only the Twisted Wedge casting between 4,000 and 5,500 rpm. RHS shipped the heads with what should have been a sufficient single 1.460-inch-diameter valvespring, but the horsepower graph reveals that above 5,800 rpm the power trailed off, leading us to think that perhaps with a better spring this head could have carried the power out beyond 6,000 rpm, which would have improved its peak horsepower number. Nevertheless, for a street engine, this head delivers excellent midrange power. Its biggest weakness may be the price. It was the most expensive of all the heads we tested.

RHS 180cc
PN 35011-01, $1,326

Peak HP 364
Peak TQ 352
Valve Sizes 2.02/1.60
Intake Port 180cc
Chamber 58cc
Valvesprings 1.460 single, max lift 0.560


TFS Twisted Wedge 180
The TFS heads appeared to be the big dog in the room when it came time for testing. We were smart enough to test-fit the heads on the Boss 302 block before testing began and discovered these heads are designed to be used with 7⁄16-inch head bolts, using restrictors in the head bolt holes. This was a simple fix, using a drill press to open up the restrictors before we could use the 1⁄2-inch ARP head bolts. The heads also required custom-length Comp Cams pushrods to compensate for the relocated valves. Once those two tasks were completed, the heads delivered the best peak horsepower and torque numbers of the entire test, knocking down an excellent 380 hp at 6,000 rpm. The Twisted Wedge heads also had the strongest horsepower curve above 4,000 rpm of all the heads tested. The only caveat to all this is the Twisted Wedge heads do limit valve lift (0.600 inch) and duration on stock pistons due to their repositioned intake valve—just so you know.

TFS 180cc
PN 51410004 M58, $1,099.96

Peak HP 380
Peak TQ 357
Valve Sizes 2.02/1.60
Intake Port 180cc
Chamber 58cc
Valvesprings 1.460 dia. dual, max lift 0.600


World Products Windsor, Jr.
World contributed the lone cast-iron head to our Ford small-block test. This head is intended for a flat-tappet camshaft, so it was outfitted with a small-diameter spring that might have limited its performance in the midrange slightly. If we were going to use these heads on a street engine, we'd disassemble them and spend the extra bucks to add a 30-degree back cut to the intake and exhaust valves to improve their overall flow. This minor tune up would really improve the flow curve and add a measureable amount of torque. If weight is a consideration, keep in mind that these iron castings weigh considerably more than the rest of the aluminum heads. If you are looking for a set of World aluminum heads, you can find them at Bill Mitchell Products.

World Products 180cc
PN 053030-1, $1,183.90

Peak HP 352
Peak TQ 342
Valve Sizes 1.94/1.60
Intake Port 180cc
Chamber 58cc
Valvesprings 1.250 single

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12 comments
Fanny St-jacque
Fanny St-jacque

quand tu va voir live un moteur sur le DYNO t en a des frissons sur tout le corps de l entendre révolutionner (super exp je le souhaite a tout les amateurs de char modifiés)

Darren Rabaduex
Darren Rabaduex

Mike Lewin, its a little late now, but the twisted wedge 180 made more power across the board out of all 6 of the heads they tested. RHS is in the list too. Zach Endicott, your Windsor Jrs are in there too.

Kurt Trimas
Kurt Trimas

Checking valve clearance, because it doesn't seem like spring tension

Jeff Mcdowell
Jeff Mcdowell

That was a lot of work to test tiny heads. What about Vic jr's and others?

Toby Waters
Toby Waters

And when all that fails.... LS it. :p

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