About Miller Hi-Speed Heads

Steve Serr has orchestrated the development of new foundry patterns, from copies of the original drawings, to cast an A-356 aluminum alloy, heat treated to T-6 specifications, version of the square-shoulder Miller-Schofield-Crager overhead valve (OHV) conversion cylinder head for the 1928 - 1934 Ford, four cylinder engines.

The design advantage the Miller holds over any F-head, is with both the intake AND the exhaust valves in the head, imperfect engine blocks with cracks between valve seats can again be put back in service. All that's needed are four good cylinders and bottom end. The CNC-machined OHV unit will accept the stock intake and exhaust manifolds and distributor, just like the original cast-iron units.

Each, Fully CNC machined, combustion chamber is 4" in diameter by 7/8" deep, producing 6.5:1 compression when bolted on a stock short block with flat-top pistons, for an increase of approximately 2.25 CR. The base of the head has been thickened from 1/4" to 1/2" inch so the owner can increase compression further by milling that surface if desired. To further strengthen the head, the long slot water passage on the spark plug side has been closed off and those on the distributor side have been reduced to 5/8" inch diameter holes, the same size as in the head gasket, reducing the possibility of water leaks. The ports remain the stock diameter (intake: 1-5/8" and exhaust: 1-1/2") with sufficient wall thickness, 1/4" inch, for future porting work, if desired, by the owner. Each unit will be pressure tested for porosity before being shipped from our facility.

The head is equipped with stainless steel 1.94" intake and 1.50" exhaust valves installed, each having 11/32" dia. stems, 5/16" deep hardened seats and cast iron guides. The valve springs, exerting pressures of 60 lbs. closed and 130 lbs. open, will be activated by shaft-mounted roller rocker arms providing greater valve lift even when retaining the stock base circle cam. 1.5:1.

The head is machined for modern 14mm by 3/4" reach spark plugs and to a depth that puts the grounding electrode in the combustion chamber, eliminating "cartridge fire". Finding the exact heat range plug your engine needs will be easy at any auto parts store.

The complete package will include: a polished aluminum rocker arm cover, cork gasket and two large brass wing nuts; finned aluminum side cover and gasket; distributor stand, gasket and distributor drive shaft; all intake/exhaust and water pump mounting holes are heli-coiled for additional strength and durability; Automotive Racing Products (ARP®) head bolts and hardened washers (studs are available for an additional fee); a head gasket, consisting of a perforated stainless steel core laminated on two sides with a facing of 75% pure graphite and aramid fiber reinforcements, with a metal fire ring around each combustion chamber; tubular steel pushrods with hardened ends and heat treated steel caps/cups for the top of the stock cam followers. Options include a leakless, Miller/Crager style water pump with stainless steel shaft, two sealed roller bearings, and a triple lipped neoprene seal. Cast Iron Exhaust manifold, computer redesigned and dyno proven tube headers, a Weber 32-36mm progressive carburetor, intake manifold, linkage and air cleaner, or Stromberg 97 carburetor look alike with electronic throttle body fuel injection also available.

"The Miller-Schofield head on a stock block, using stock manifolds and cam, with no other changes but a 1-1/4 Miller carb, was alleged to produce 86 bhp at 3200 rpm, over twice the output of a stock Model A." And "One aesthetic advantage of (Leo) Goosen's (Miller-Schofield head) design over (George) Riley's is that the former has a deep, powerful exhaust note, like a Miller Four racing engine. The Riley is an F-head using stock exhaust ports in the block, and it maintains the unimpressive ratchety sound of a stock Model A" Mark L. Dees, The Miller Dynasty, revised and expanded second edition (1994), page 308.

Special thanks to the following individuals for their assistance and encouragement: original Miller-Schofield Hi-Speed Head drawings: Gordon White, courtesy of Leo Goossen Archives; engine builder: Phil Andrews, Andrews Engineering; pattern maker: Tom Roberts Designs; CNC machining: Tom Huggins, Performance Industries; rocker arm assembly: Gary Patrick, Rocker Arm Specialist; advice and referrals: Roland Hass, Super Vacuum Mfg. Co,; Jay Steel, Taylor Engine; foundry: Mike McKeen, Buddy Bar Casting; gaskets: Armin Brown, Best Gasket; and 4.030" fire-ringed head gasket: Bob Eineicher, Performance Gasket Concepts.

Each unit will have a numerically sequenced serial number and a date of manufacture engraved inconspicuously on the exterior. Interested individuals may contact Steve Serr by any means printed below.

Phone: (805) 647-2766
Fax: (805) 647-7578

model A truck