Priding themselves on being engine builders as well as manufacturers, the Indy team employed some rather unique tricks to their PN 440-SR CNC cylinder heads. Instead of simply bolting on an off-the-shelf head, they used their CNC castings as a foundation for a trick set of heads. Rather than using the standard length valves, Indy consulted with Randy Longstreet of Manley Performance Products who recommended a set of titanium 2.300 inch intake, and 1.76 inch exhaust valves with longer than standard stems. While there are several advantages to longer valves, the main advantage is that a more aggressive, higher lift camshaft can be utilized without worrying about valvespring coil bind, or retainer to guide clearance.
Unfortunately, longer valve stems play havoc on the valvetrain geometry, requiring the rocker arms to be relocated. Since our rules prohibited welding on the head, Indy got creative and manufactured specially offset bushings and shims to move the rocker studs away from valves. Larry Tores of T&D Machine Products helped to calculate valvetrain geometry, recommending T&D PN 8216 rocker arms with 1.7 intake and exhaust ratios. The Indy crew also used a somewhat unconventional method to "unshroud" the intake valves, but you'll have to ask them about that trick because we're not telling all their secrets.
To top off their long block, Indy made the logical choice of their PN 440-15 tunnel-ram intake manifold. Knowing that a tunnel-ram produces more peak power, and since our contest factors peak torque and horsepower instead of averages, using a tunnel ram and dual four-barrel induction just made sense. To mix the fuel and air, and since total induction volume was limited to 1,350 cfm, Indy chose a pair of Barry Grant 675-cfm Race Demon carburetors. Topped with Indy PN 440-7PC cast aluminum valve covers and ignited by an MSD PN 8546 Pro-Billet distributor, this combination screamed to 758 hp and 601.6 lb/ft of torque to win this year's Engine Challenge. We congratulate Indy on their win and thank them for sharing what it took to put together this winning combination.
2008 Participants
Indy Cylinder Head
Indianapolis, IN 46239
317/862-3724
indyheads.com
Schurbon Engine and Machine
Maquoketa, IA 52060
563/652-3100
JMS Racing Engines
El Monte, CA 91732
626/579-4567
jmsracing.com
JD Engine and Machine
Columbia, MO 65203
573/445-4550
Chenoweth Speed and Machine
Morton, IL 61550
309/266-8084
chenowethspeedandmachine.com
Cederstrand Racing Engines
Brea, CA 92821
714/653-4523
Cederstrandracingengines.com
Promax
Indianapolis, IN 46222
317/241-3432
sales@promaxcarbs.com
Editor's Note: If you want to hear the Indy Cylinder Head engine run, go to our web site, www.moparmusclemagazine.com, and check out the video section. Don't forget to turn your volume up.
Rather than use off-the-shelf...
Rather than use off-the-shelf heads, Indy chose to utilize Manley titanium valves with a longer than standard valve stem, allowing very high valve lift.
Indy's CNC port job makes...
Indy's CNC port job makes the most of the SR cylinder head. In fact, the only hand porting done was at the port entrance to match the intake manifold.
Longer valves may let you...
Longer valves may let you run more lift, but to correct valvetrain geometry the rocker arm needs to be moved up and away from the valve. Since our rules prohibited welding the heads, Indy made these trick offset threaded bushings to relocate the rocker shaft studs.
Special spacers had to be...
Special spacers had to be made to properly locate the rocker shafts in order to work with long-stem valves. This would have been easier to do by welding the heads and re-machining the rocker stud threaded holes, but doing it this way made it legal by our rules.
Knowing that tunnel-rams make...
Knowing that tunnel-rams make power, Indy chose their PN 440-15 intake manifold and topped it with a pair of Barry Grant Race Demon 675-cfm carburetors, for a total induction volume of 1,350 cfm, the contest limit.
On the dyno, Indy's hard work...
On the dyno, Indy's hard work became apparent. At nearly 760 hp and over 600 lb/ft of torque on pump gas, this is one incredible 440. We congratulate Indy Cylinder Head on their win in the 2008 Amsoil/Mopar Muscle Engine Challenge.
With the modifications complete,...
With the modifications complete, Indy used T&D Machine Products PN 8216, 1.7 ratio rocker arms to actuate the valves.