Today's small block Ford street engine builder has it easy. Not all that long ago, the small block fan's only choice for Ford cylinder heads was the classic 351W Ford heads swap on a 302. Today, the aftermarket lineup of Ford cylinder heads has plenty of castings from which to choose. We'd love to test 'em all, but we decided to line up as many performance small block Windsor Ford heads as we could find, as long as they were available complete for less than $1,350 for the pair. These Ford cylinder heads all feature between 170 and 180cc intake port volumes and offer excellent performance potential over even the best production iron 5.0L heads. To pull this off, we needed a durable mule, so we chose Ford Racing's Boss 302 345hp crate engine that comes with a set of aluminum heads and actuated by a 0.480-inch lift B303 hydraulic roller cam, and 9.0:1 compression. To complete the Boss, we added an Edelbrock Performer RPM intake, a Holley 750 cfm mechanical secondary HP carb, MSD distributor, and a set of open exhaust dyno headers, and we were ready to rumble.
It's also worth mentioning that due to deadline pressures, Dart and Pro Comp Electronics also offer small block Ford heads that fit within our price prerequisite, but for a variety of scheduling reasons, they didn't make the test. The Dart castings would have been the Iron Eagle versions while the Pro Comp's are affordable in aluminum.
As with our small-block Chevy head test published in the Sept. '12 issue, we will evaluate each of these small block Ford cylinder heads using several different categories in addition to peak torque and horsepower. We evaluated each head on the flow bench, average overall power, and we calculated average horsepower-per-dollar. We'll squeeze all of this into these few short pages, which means we have a long way to go and a short time to get there. So get comfortable, slip on your Ford-colored glasses, and hang on.
Edelbrock Heads: E-Street Ford Cylinder Heads
This made-in-the-USA head is Edelbrock's value leader. Edelbrock heads are available in two different versions with either 1.94- or 2.02-inch intake valves. Our test heads came with the larger intakes that clearly contributed to these heads' strong showing. The E-street came in second in peak horsepower and a very close third in average horsepower and torque. The Edelbrock heads showed a little weakness in the midrange, something that could probably be rectified by adding a 30-degree back cut to the intake valve. At less than $950 for the pair, these Edelbrock heads may be the best bang-for-the-buck investment of all the Ford heads in this test. Combine Edelbrock quality with excellent power and a highly competitive price, and the E-Street Edelbrock heads strike us as an excellent choice.
Ford heads: Edelbrock E-Street 170cc
PN 5025, $935.95
Peak HP 371 Peak TQ 346 Valve Sizes 2.02/1.60 Intake Port 170cc Chamber 60cc Valvesprings 1.250-inch single, max lift 0.550
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
Peaks and Averages
We should stress that during testing we optimized each set of heads for timing and jetting and then ran the engine with two near identical runs, which were then averaged to come up with the final power numbers. While peak horsepower is a quick evaluator, we prefer to use average power in these comparisons because it always produces a better picture of overall performance. But as we've seen before, the heads that produce the best peak power also do so throughout the entire rpm band. That's what the TFS Twisted Wedge heads did. Not only did the TFS heads produce the most peak power but also the best average torque and horsepower. The RHS heads produced the next closest average horsepower and torque, with the Edelbrock and Ford heads very close behind. The power numbers are so close that if we had tested these heads in a typical street car, it's doubtful we would have seen much of a difference in performance among the middle four heads. Throw a blue oval flag over the RHS, Edelbrock, and Ford heads, and the performance is very similar.
We certainly don't want to ignore the peak numbers, and that's where the TFS Twisted Wedge heads really earned the spotlight. The TFS heads made an honest 380 hp, but what we found surprising was how well the Edelbrock E-Street head did with a peak of 371, substantially better than Ford Racing's 362hp Third Place finish. The finish order for peak torque realigned slightly with TFS out front, RHS coming in a strong Second, with Edelbrock and Ford tied for Third.
We used a set of Comp Cams Ultra Pro Magnum roller rockers for all the heads except for the Ford Racing heads that require a net lash style rocker. Comp also supplied the various length Hi-Tech 0.080-wall pushrods necessary to complete the test, especially for the Twisted Wedge heads. That’s an additional cost that you might want to consider.
Average Power
Avg. TQ
Avg. HP
TFS
341.4
294.3
RHS
335.8
288.8
Edelbrock
332.5
286.2
Ford
332.3
285.4
Flo-Tek
330.5
283.1
World
327.1
280.7
Power Chart
Test 1 (TQ1/HP1): World Windsor, Jr.
Test 2 (TQ2/HP2): Edelbrock E-Street
Test 3 (TQ3/HP3): Flo-Tek / Speedway Motors
Test 4 (TQ4/HP4): Ford Racing
Test 5 (TQ5/HP5): Racing Head Service
Test 6 (TQ6/HP6): Trick Flow Specialties Twisted Wedge
RPM TQ1 HP1 TQ2 HP2 TQ3 HP3 TQ4 HP4 TQ5 HP5 TQ6 HP6 3,000 311 177 312 178 314 180 312 178 309 176 312 178 3,200 306 187 312 190 317 193 314 191 313 191 313 191 3,400 310 201 311 201 321 208 318 206 321 207 318 206 3,600 325 223 320 219 329 225 327 224 329 225 330 226 3,800 329 238 326 236 333 241 331 240 332 240 335 242 4,000 332 253 332 253 336 256 334 255 337 257 339 258 4,200 337 269 339 271 341 272 338 271 343 274 345 276 4,400 342 287 346 290 346 290 345 289 350 294 353 296 4,600 341 298 345 302 347 304 346 303 351 308 356 312 4,800 337 308 344 314 343 314 344 314 349 319 357 326 5,000 335 319 343 326 339 323 342 326 347 331 357 340 5,200 334 331 344 341 336 333 340 337 347 343 355 351 5,400 332 341 344 354 333 342 339 348 345 355 353 363 5,600 326 347 340 362 326 347 333 355 339 362 350 374 5,800 317 350 331 366 315 348 325 359 329 364 343 379 6,000 308 352 322 368 297 340 316 361 317 362 333 380 6,200 --- --- 314 371 --- --- 307 362 --- --- 320 378 Peak 342 352 346 371 347 349 346 362 352 364 357 380 Avg. 327.1 280.7 332.5 286.2 330.5 283.1 332.3 285.4 335.8 288.8 341.4 294.3
Horsepower Graph
You'll notice that we attenuated the horsepower graph to include just the power curve between 4,000 and 6,200 rpm. We did this to expand the scale to show the differences in power near peak horsepower. While the TFS head looks much stronger than the Edelbrock version above 5,500 rpm, the maximum differential is only 13 hp at 5,900 rpm. While that's significant, this is only at one rpm point. It is more important to evaluate the entire length of this horsepower graph. When you do that, you can see that the TFS head did substantially better than all the other heads from about 4,400 rpm and above. You will certainly feel that in the car. We should also mention that, while we didn't test a stock iron casting, it should be clear that even the heads on the lower end of our test would still be an improvement over stock factory castings.
Cylinder Head Peak HP Peak TQ TFS 380 357 (1st) Edelbrock 371 346 (tie 3rd) RHS 364 352 (2nd) Ford 362 346 (tie 3rd) World 352 342 (6th) Flo-Tek/Speedway 349 347 (5th)
Dollar Per Horsepower
Peak power numbers are always fun to throw around, but car crafters are also very astute at determining what all that power will cost. To minimize the grief of doing the math yourself, we averaged the horsepower between 3,000–6,000 rpm and then divided that into the cost of a pair of heads. The winner in this evaluation is almost always the least expensive head just because of the way the math formula works. This particular evaluation only works, however, if lowest cost is the highest priority. If it is, then you know what you need to do. But for perhaps a majority of enthusiasts, this evaluation may be too simplistic. If this becomes a bit more subjective by adding in power (and why wouldn't you?), then the second least expensive heads—the Edelbrock E-Street heads—really begin to stand out. If we've muddied the waters a bit, it's only the result delivering more information on the way to a decision.
Average Dollar Per Horsepower
Flo-Tek / Speedway
$2.61
Edelbrock
$3.28
TFS
$3.73
Ford
$3.92
World
$4.21
RHS
$4.59
Parts List
Description
PN
Source
Price
Edelbrock E-Street
5025
Summit Racing
$935.95
Ford Racing X307
M-6049-X307
Summit Racing
1,119.90
Flo-Tek/Speedway
7223000
Speedway Motors
739.98
RHS 180
35011-01
Summit Racing
1,326.00
TFS 180
51410004-M58
Summit Racing
1,099.96
World Windsor, Jr.
053030-1
Summit Racing
1,183.90
Edelbrock RPM int.
7521
Summit Racing
257.95
Holley 750 HP
0-82751
Summit Racing
499.95
Fel-Pro head gasket
1011-2
Summit Racing
35.75
Fel-Pro int. gasket
1262
Summit Racing
21.25
Comp rocker arms
1831-16
Summit Racing
399.95
Comp pushrods
7752-16
Summit Racing
134.95
Comp 10w30 oil
1594
Summit Racing
39.75
Comp valve cover
282
Summit Racing
151.95
Autolite spark plugs
AR3934
Summit Racing
28.00
Autolite spark plugs
AR25
Summit Racing
47.60
Autolite spark plugs
AR472
Summit Racing
31.60
Permatex Rt. Stuff
29208
Amazon
13.15
MSD distributor
8598
Summit Racing
241.95
MSD plug wires
31189
Summit Racing
82.95
Ford roller rocker kit
M-6564-B351
Fordracingdirect.com
465.95
ARP head bolts
154-3601
Summit Racing
46.54
Ford Racing Boss 302 engine
M-6007-X302B
Summit Racing
6,599.95
Intake Port Flow (cfm)
Intake Port Flow (cfm)
Ford Int. RHS Int. World Int Flo-Tek Int. Edel Int. TFS Int.
0.1 60 59 56 49 58 63
0.2 116 119 117 102 119 139
0.3 171 168 162 152 167 198
0.4 214 194 189 192 211 239
0.5 228 207 206 203 235 254
0.6 236 215 216 215 241 252
Exhaust Port Flow (cfm)
Exhaust Port Flow (cfm)
Ford Exh RHS Exh World Exh Flo-Tek Exh. Edel Exh. TFS Exh.
0.1 50 50 50 44 50 52
0.2 96 102 98 90 99 102
0.3 131 135 130 128 134 128
0.4 161 150 149 144 159 154
0.5 174 155 158 148 172 172
0.6 179 158 161 149 178 181
Conclusion
Like we said, if best power or least price is your only concern, then the decision is easy. But for the rest of us, choosing a cylinder head might be a complex algorithm of price, power, brand loyalty, ease of installation, head bolt size, and maybe even shoe size if you're that compulsive. If ultimate power is not the most important point, then you could easily choose any of these heads and make a good decision. That may or may not make your ultimate choice any easier, but if so, you can thank us later. And, yes, this next bit is unashamed self-promotion, but the next time some lame dude spouts off about how he gets all his information off the Web—ask him to show you the last time he read a comprehensive test like this from a free Web-based publication. Car Craft is one of the few magazines that is willing to do this kind of extensive and expensive technical testing for our readers. And you get it for the price of a subscription. That, my friends, is the deal of the century.
