When we first had the idea of building a Junkyard Jewel out of Ford's much beleaguered but widely produced 2V 4.6L (Apr. '08), we knew our biggest stumbling block was going to be the heads. Even with 46mm oversized valves in '99-and-later Power Improvement (PI) heads and the most extensive porting magic Ford Performance Solutions could work, we were still barely cracking 200 cfm of airflow. While that was a significant improvement over stock, it was nowhere near the breathing room we wanted for our small-displacement, SOHC engine. Wehn we first built our 4.6 there were no aftermarket heads available. That has changed, thanks to Trick Flow Specialties (TFS).
Finally, an aftermarket cylinder head for Ford's two-valve modular motor.
First a recap of the original project. Our 4.6 started out as a 117,000-mile '97 Crown Victoria engine that we found on Craigs-list for $400. Originally rated at a measly 210 hp and 270 lb-ft, it was far from hot rod worthy. We ripped off the fuel-injection mess, converted it to later-PI-style heads and cams, topped it off with an Edelbrock Victor Jr. intake and a Demon carb, and let an MSD 6-Mod controller handle the timing. Right off the bat, we had 313 hp. Tuning, porting, bigger valves, and a Comp 274H cam (we mistakenly reported the use of a 278AH in the original story) rewarded us with a best of 396 hp. Not bad, but the bottleneck was obvious.
Besides flow limitations, the valve arrangement in the Ford PI heads severely limits the lift and duration that can be installed with stock pistons. Comp's 274H with 0.500 valve lift and 236/240 duration at 0.050 is pretty much the biggest stick that will clear.
With millions of these things stagnating in Mustangs, F-150s, T-birds, and Crown Vics, it raised the question, "Why had no one tapped the market?" The answer lies in the design of the heads themselves. Rather than using bearings like standard cam-in-block engines, mod motor cams ride directly on the heads themselves. Redesigning that alone would require incredibly precise OE-level tooling, a significant investment. But perhaps even more daunting, as an insider at a large cylinder head company once explained to us, "The original Ford design really can't be helped. To do it right, the heads need to be reengineered clean slate." And that's a major engineering undertaking.
Valve-to-piston clearance changes with Trick Flow's Track Heat 185s (right). The intake valve is moved to the opposite side of the cam rather than the single side placement on the Ford PI (left). If it looks vaguely familiar to 2.3 Ford fans, that's because Trick Flow used the four-banger head as a rough starting point for the layout.
The demand is there, however, so TFS engineers took on the challenge to deliver legions of Mustang owners some real flow numbers they could work with. The head needed to retain stock intake and exhaust port locations for easy transplanting into existing cars, but everything else was fair game. Combustion chamber, valve size and location, and port and runner designs were all rethought, and that hard work didn't disappoint. With a swap of the cylinder heads and Trick Flow 0.580-inch-lift cams on our 4.6 Junkyard Jewel, we were rewarded with 58 peak horsepower and 33 lb-ft over our best efforts with Ford PI heads and the Comp cam with less lift. It's a true case of castoff junk meets state-of-the-art parts, and the result is the most naturally aspirated power per cubic inch we've ever pulled out of a Junkyard Jewel engine.
This cutaway shows the main rationale behind the valve relocation; note that the OE Ford design (left) has an 11/11-degree negative angle on the intake valve that impedes flow. The Trick Flow head moves the intake valve to a 9/9 angle and places it in line with the intake port, concurrently putting the valve more in line with the short-side radius.
HEAD FLOW DATA PI STOCK PI PORTED TFS STOCK TFS PORTED LIFT IN. EX. IN. EX. IN. EX. IN. EX. 0.100 54 55 57 56 58 49 71 60 0.200 102 91 107 98 125 101 139 108 0.300 139 121 154 133 175 143 195 151 0.400 159 137 179 169 224 174 238 183 0.500 169 142 194 182 250 179 268 197 0.600 175 150 203 185 252 188 291 206 Note: Lift is in inches; flow is in cfm.
TRICK FLOW CAM SPECS
PN TFS-51802002
INTAKE
EXHAUST
Valve lift (inches)
0.580
0.580
Duration at 0.050
234
234
Centerline
110
118
Lobe separation
114
Note: All values in degrees unless stated
otherwise.
DYNO RESULTS RPM HP LB-FT 3,400 212 317 3,600 221 322 3,800 237 327 4,000 252 331 4,200 269 336 4,400 292 347 4,600 319 364 4,800 344 376 5,000 365 383 5,200 386 390 5,400 399 388 5,600 408 382 5,800 419 379 6,000 433 379 6,200 446 377 6,400 453 372
454HP 4.6 2V RECIPE Parts Price 4.6L from a '97 Crown Victoria with 117,000 miles $400.00 TFS heads 2,095.95 TFS Track Max cams (TFS-51802002) 479.95 Comp Cams valvesprings (PN 26113-16) 166.87 Trick Flow valve covers 198.95 Edelbrock Victor Jr. carb intake with MSD 6011 module 759.95 575-cfm Mighty Demon 549.99 Wilson Manifolds 1-inch tapered spacer 128.75 Autolite 764 spark plugs 12.72 K&N oil filter 10.99 5 quarts Mobil 1 synthetic oil (10W-30) 36.00 '99-and-later Ford ignition coils (junkyard) 75.00 BBK chrome full-length headers 422.99 Fel-Pro valve cover gasket set 36.99 Fel-Pro 4.6 PI intake gasket set 43.99 Fel-Pro head gaskets 48.99 Fel-Pro exhaust gaskets 11.99 4.6 head bolts 69.00 Timing chain guides (PI style) 60.00 Total $5,609.07
