Knuckle lifter blocks - two styles

[Hollywood]

I am not sure when exactly the transition was made or why, but I've narrowed it down. I checked out a nice original 40 motor and it had the early style. I saw a restored 42 on Matt Olsen's blog with the late style (beveled). I have two 41's and one has the late and one has the early.
I originally figured they changed when the pushrod tubes changed in 1940 but that does not appear to be the case.

[BigLakeBob]

Hey Bob,
I can use at least one of those blocks if it isn't chrome. PM me.
Thanks
Robbie

Sent you a PM early this morning.

[Rubone]

Hey Bob,
I can use at least one of those blocks if it isn't chrome. PM me.
Thanks
Robbie

[Jerry Wieland]

For sure the square top lifter blocks are early. My personal belief is that the bevel top lifter blocks are a mid production 1942 and up item. No references to quote, just lots of looking at original bikes. Seems to have changed at the same time they got rid of the so called 1941 only oil pump.

Never seen them OEM on a 41 and down bike. JWL has original paint bikes that seem to back this theory up. Jerry

[BigLakeBob]

I came across 2 rear knuckle lifter blocks I want to trade, but want to make sure I describe them correctly. Is there a different style for different years as asked at the start of this thread? The ones I have, have bevels at the top. Thank you.

My 47 has beveled tops

My 38 EL has the bevels.

If I recall correctly 41 was the first year the bevel top blocks were used. The best way to get a response on most tech boards is make an incorrect statement. The overwhelming need to correct an error will set those typing fingers to tapping!

Any ideas, anybody?

Lonnie

I've noticed that there are two different types of knuckle lifter blocks, though Bruce Palmer's book only mentions one type without describing it. My question is, to what years do each type apply:

1> Type 1 - At the top, where the pushrod tube sits, the top edges are beveled towards the tube.

2> Type 2 - At the top, again where the pushrod tube sits, the top edges are squared off - no bevel.

Since I am looking at these blocks on the motors, I cannot state what the casting numbers or marks (if any) indicate.

Any ideas?

Thanks,
Lonnie