Many Model A and T enthusiasts know of Bill Stipe through his work to improve and reproduce quality new camshafts for our engines. This was a big undertaking, and the hobby has certainly benefited from his perseverance and careful work.
The purpose of this page is to highlight some of the new flathead Ford camshafts Bill makes for the Model A and B engine, and a comparison to stock original Ford A and B cam specifications.
These cams are entirely brand new, made by Bill in the USA, and are of the highest quality. They are machined from SAE 8620 steel billet, finish-ground, and heat treated (carburized). All of Bill's cams also come with the Model B fuel pump lobe.
Pictured above is a rack of new Model A/B cams made by Bill. Nice!
The original Model B Ford camshaft lobe profile required 1.187 inch base diameter tappets (push rods), which are no longer available. All of Bill's cam lobe profiles and push rod acceleration ramps are designed specifically to use the readily available 1.117 inch base diameter self-locking tappets, along with Bill's push rod clearance recommendations.
The inferior ~1.000 inch (or less) base diameter jam-nut undersize tappets on the market should never be used with any Stipe camshaft or original Model B camshaft.
The use of those too-small 1 inch tappets can result in severe damage to both themselves and the camshaft lobes. Only use the 1.117 (or larger) base diameter tappets with any Model A or B camshaft.
Bill's camshaft designs offer significant dyno-tested and proven performance gains over original Ford camshafts. These new cams each have lobe designs, timing, lift, and duration characteristics optimized for specific usages.
|Camshaft Specification||Model A
|Valve Open Duration||236||244||244||246 I
|Lobe Separation Angle||112||114||114||114 I
|Valve Overlap Angle||12||16||16||22||28||crankshaft degrees|
|Req'd Push Rod Base Diameter (min)||1.117||1.187||1.117||1.117||1.117||inches|
|Intake Lobe Design Lift||0.302||0.334||0.330||0.340||0.340||inches|
|Intake Valve Design Clearance (gap)||0.015||0.015||0.012||0.012||0.012||inches|
|Intake Valve Lift||0.287||0.319||0.318||0.328||0.328||inches|
|Intake Valve Opens BTDC||7.5||8||8||9||13||crankshaft degrees|
|Intake Valve Closes ABDC||48.5||56||56||57||60||crankshaft degrees|
|Exhaust Lobe Design Lift||0.302||0.341||0.330||0.340||0.340||inches|
|Exhaust Valve Design Clearance (gap)||0.015||0.022||0.012||0.012||0.014||inches|
|Exhaust Valve Lift||0.287||0.319||0.318||0.328||0.326||inches|
|Exhaust Valve Opens BBDC||51.5||56||56||57||61||crankshaft degrees|
|Exhaust Valve Closes ATDC||4.5||8||8||13||15||crankshaft degrees|
|BTDC||Before Top Dead Center|
|ABDC||After Bottom Dead Center|
|BBDC||Before Bottom Dead Center|
|ATDC||After Top Dead Center|
The IB330 is essentially a re-engineered copy of the original Ford Model B camshaft, but designed for the currently available 1.117 inch base diameter self-locking tappets. It is designed for great low end torque and is excellent for touring. A great new improved performance cam for any basically stock Model A or B engine.
The IB340 is also engineered for touring, with great low and mid range torque in the 1600 to 3000 RPM range. It is best run with larger intake valves and larger carburetor and 6:1 or 7:1 compression ratio cylinder head. It is also made for the currently available 1.117 inch base diameter self-locking tappets. A great cam for any engine with upgraded carburetor, manifolds, cylinder head, etc.
The RR340 is engineered for low and mid range power, and is made for the currently available 1.117 inch base diameter self-locking tappets.