Model A & B

Ford Garage

Bill Stipe's Camshaft Specifications

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
A-6250
Model B
B-6250
Stipe
IB330
Stipe
IB340
Stipe
RR340
Units
Valve Open Duration 236 244 244 246 I
250 E
253 I
256 E
crankshaft degrees
Lobe Separation Angle 112 114 114 114 I
112 E
112.75 camshaft degrees
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
Piston Position
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.

Contact Bill Stipe and get yours today! 920-467-2895
Follow this link to Bill Stipe's Specialty Motor Cams web site.


More Camshaft web pages on Ford Garage:

  1. Model A & B Original Ford Camshaft Specifications
  2. Model A & B Original and Reproduction Valve tappet (Push Rod) Details
  3. Model A & B Camshaft Timing Gear Varieties
  4. Model A & B Camshaft to Crankshaft Positioning
  5. Model A & B Bill Stipe Machine Shop

March 2010