JD A and B heads????

[GreenEnvy]

Just curious on the A and B, what is the difference between a the normal head and the "ramp" head that came out in the early 40s. And then what is the difference between the "ramp" head and then the "cyclonic" head that came out on the new A/B series in the late 40s.

 

[JIM MN]

It has to do with the cast iron raises around and by the intake valves to swirl the air around to mix the air with the gas vapors? Ramp-Cylclonic- eye brow heads. It is all about getting more horsepower. A more efficient use of gasoline to get more power.

 

[GreenEnvy]

It has to do with the cast iron raises around and by the intake valves to swirl the air around to mix the air with the gas vapors? Ramp-Cylclonic- eye brow heads. It is all about getting more horsepower. A more efficient use of gasoline to get more power.

I've never been inside a B or A engine so I am just going off of what I read. I know the cyclonic heads used that "eyebrow" around the intake to swirl the incoming fuel/air which according to my sources was introduced in 47" on the new A and Bs. What is the difference between that head and the "ramp" head that came before it which came out in 1940 for the A?? Or is there a difference? And what is the difference between the "ramp" head and what came before that?