Why Use 'B' Camshaft?
- Thread starter pbishop
- Start date
Synchro909
Well-known member
If all else is left untouched, not much.
Kurt in NJ
Well-known member
on my car the original cam it got no more than 18 mpg, and no faster than 53 mph, then used unworn "B" cam, valve seats to get valve in proper heigth instead of sunk in the block---67 mph, 23 mpg at 65, I can't say how much the valve seat added, but the car is totally different, ----this is a real "B" cam ,not regrind
Jim/GA
Well-known member
Compared to a stock A cam, the B cam had a slightly longer duration (degrees of cam rotation that the valve is open) and had a little higher lift (valves open a bit more). So the engine can breathe a bit better with a B cam. You get a bit more power with this setup.
Last edited:
Kevin in NJ
Well-known member
It should be noted if you intend to switch to a B cam you also must change to wider head tappets.
Purdy Swoft
Well-known member
I agree . If the B cam is used with the Model B (C) head , Larger B size ports , model B carb. and intake manifold , you should get about a 10 horsepower increase . The C head gave the B engine nearly 7 horsepower . The other mentioned B parts gave a little better than three horsepower. See the Piranio's dyno tests. Don't expect to feel any real seat of the pants improvement if only the B cam is used by its self
Purdy Swoft
Well-known member
An even more important consideration is that original model B lifters were LONGER than model A lifters . If a model B cam is uced , it will be necessary to either use modern longer stem valves or adjustable lifters or the valve stems will not meet the lifters for adjustment. In other words there will be a large gap between the valve stem and the lifter .
Also in addition to differences mentioned above ... if an original un-reground B cam is used the exhaust valve tappet clearance is 0.022 ... yes 0.007 wider than Model A clearance.
The wider clearance applies only to ORIGINAL Exhaust valve tappets with un-reground camshaft.
If you have a RE-Ground Model B "touring" cam then use the clearances quoted by the cam grinder.
The wider clearance applies only to ORIGINAL Exhaust valve tappets with un-reground camshaft.
If you have a RE-Ground Model B "touring" cam then use the clearances quoted by the cam grinder.
Last edited:
brett4christ
Senior Member
So, If I want to use a Model B cam in my Model A, can I use the Model B cam followers with Model A valves and springs? I will also be using the Model A Police head ("B" casting mark). Everything else is stock A or aftermarket (Mallory distributor, Ansen single carb intake, Holley 94,).
