Classic Inlines Ford 200/250ci Aluminum Cylinder Head Specifications


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Classic Inlines
603 W Pecos Ave
Mesa, AZ 85210

Aluminum Cylinder Head - Specifications

Ford Inline Six - Aluminum Cylinder Head (144/170/200/221/250ci)
Intake	Valve Lift / Flow
Intake	.100	.200	.300	.400	.500	.600
US Log	45 cfm	87 cfm	108 cfm	119 cfm	124 cfm	127 cfm
OZ 250	63 cfm	101 cfm	133 cfm	155 cfm	156 cfm	156 cfm
CI Alum	52 cfm	99 cfm	143 cfm	180 cfm	201 cfm	210 cfm
Ported CI	55 cfm	103 cfm	159 cfm	196 cfm	223 cfm	231 cfm
Exhaust	Valve Lift / Flow
Exhaust	.100	.200	.300	.400	.500	.600
US Log	36 cfm	68 cfm	91 cfm	98 cfm	103 cfm	105 cfm
OZ 250	36 cfm	68 cfm	91 cfm	98 cfm	103 cfm	105 cfm
CI Alum	40 cfm	79 cfm	111 cfm	144 cfm	164 cfm	174 cfm
Ported CI	44 cfm	87 cfm	122 cfm	159 cfm	179 cfm	184 cfm

Miscellaneous Specifications
Chamber Size	56cc	Water Temp Sender	1/8" NPT
Intake Valve	1.840	Manifold Bolt Size	3/8" x 16 x 1"
Exhaust Valve	1.500	Header Bolt Size	3/8" x 16 x 1"
Head Weight	32 lbs	Head Stud Length	7@4" and 7@5.5"

Spark Plugs
Manufacturer	COLD-----<-----Heat Range----->-----HOT
Autolite	n/a	3932	3933	3934	n/a
Autolite Racing	AR3931	AR3932	AR3933	AR3934	AR3935
NGK	R5671A-11	R5671A-10	R5671A-9	R5671A-8	R5671A-7
Champion	C55C	C57CX	C59CX	C61CX	C63C
Spark Plug Specs	Thread: 14mm - Reach: 3/4" - Hex: 5/8"

"CAUTION" ........ Miscellaneous Notes and Tips........."CAUTION"

Reduce Ignition Timing - Make sure you reduce the ignition timing to prevent pre-igniton and/or detonation. Failure to do so may result in severe engine damage. According to our design engineers, the ignition timing may be reduced by as much as 8-10 degrees, so start low and work up. Also see our tech article on ignition timing.

Check and Verify - Check pushrod length and side clearance, rocker arm geometry, valve spring coil bind, cylinder head torque values, intake and header clearance, hood clearance, carb linkage or throttle cables, fuel lines, and vacuum connections.

Always use Anti-Seize - All bolts, studs, screws, pipe plugs, spark plugs, sending units, or anything that threads into aluminum must be coated with an anti-seize lubricant.

Studs vrs Bolts: We recommend using studs instead of bolts, whenever possible, for several good reasons. Studs offer a more uniform and accurate torque load, as well as increased clamping force, which aids in the prevention of gasket failures. Studs make it easier to assemble an engine, and insure the proper alignment of gaskets. Plus they greatly reduce the likely hood of stripping aluminum threads, caused by over torquing.
See our tech article on ARP Studs for more information and installation tips.

Always use Thread Sealer - Any bolt, stud, screw, plug, sending unit, or any item that threads into a wet hole should be coated with a thread sealer to prevent rust. One such bolt (stud), is the head bolt (stud) closest to the thermostat. It is often missed as it is the only head bolt (stud) that threads into a wet hole.

Autolite Racing Plugs - We recommend using Autolite Racing plugs or an equivalent. See the chart above for other recommended spark plugs and heat ranges.

Coldest Spark Plug 1st - Always start with the coldest spark plug first, then move up the heat range as required. A plug which is to cold will simply foul out over time, which can be replaced with a hotter plug as needed. A Spark Plug which is to hot may cause pre-ignition and/or detonation, resulting in severe internal engine damage.

Water Temp Sender - The water temp sending unit is smaller than a stock sending unit, so make sure you pick up a 1/8" NPT Water Temp Sending unit from your local parts supplier. Be sure to coat it with thread sealer, but not to much.

CC and Surface Mill - Out of the box combustion chamber sizes vary from 55-57cc's, with the average size being 56cc's. For best results, cc the cylinder head so that all chambers are within one cc, which translates to roughly one tenth of a point in C/R on
a 200ci motor, less on a 250ci. Then surface mill the cylinder head so that the desired chamber size (compression ratio) is achieved. This will vary depending on deck height, head gasket thickness, cylinder and gasket bore size, and combustion chamber size. We recommend a C/R of 9:1 to 9.5:1 for street applications. Race builds may utilize higher compression ratios, but caution must be observed to prevent detonation and/or pre-ignition. Extreme compression ratios may require the use of water injection or other means of preventing pre-ignition and/or detonation. Warning: High C/R's, pre-ignition and/or detonation, may (will) result in severe engine damage (see our warranty).

Check all Gaskets - Cylinder head, intake, and exhaust gaskets should be checked and trimmed accordingly, so as not to cause any interference or obstructions. Check intake and exhaust gaskets for any interference in the ports and runners, as this may create turbulence, resulting in reduced air flow and performance. Check head gaskets for correct size and alignment of water ports and oil passageways, as any blockage may result in severe engine damage. Always use the appropriate gasket sealer.

Maximum Air Cleaner Size - In most applications a 10" round air cleaner is the maximum size allowable due to shock tower clearances. Oval may also be used.

Note: While our universal intake manifolds accept 2V and 4V carbs, with the proper adaptor, they are not a simple bolt on installation. While the 2V is fairly straight forward, the installation of a 4V carb may present several obstacles to overcome, including but not limited to manifold and carb clearances, carburetor linkage, and automatic transmission kick-down linkage. See Clearance Issues for more information.

Note: If you have a tip or suggestion to share, which will help future customers with their installs, please send us a detailed message via E-mail. Thanks.