Cam Timing Gears Inquiry

[keithb7]

I’m Interested in learning why they may have changed up the cam timing gears width and chain. 
 

Left is 1953 Canadian 25” long 228 ci engine. Dodge. 
 

Right is 1949 Canadian 25” long 218 ci engine. Dodge. 
 

Although the gears are the same OD and pitch, the chains are not interchangeable.  The double row gear is slightly wider.  Forgot to mic them to compare. Wondering why they changed this up? From wider In 49 to narrower in 53 in my examples. 
 

 

Edited December 13, 2020 by keithb7

[Loren]

If I can guess, was wide chain creates more friction even though it can carry a higher peak load.

On the cars I used to work on they went from single row (bicycle type) cam chain to double row then back to single row.

The double row chains were the only ones I ever needed to change. They went through guide plates, tensioners and the chains themselves.

From that experience I'd say the narrower chains are more desirable.

Of course if you could use a gear drive, well then there's nothing to worry about. But then that's a whole other set of issues.