Curious about straight cut timing gears . . . how does the cam thrust into proper position without the helix? I would think that it would tend to oscillate back and forth . . .
The oil pump/distributor drive gears also put thrust onto the camshaft! The 4/6 cylinder GM engines have a camshaft retainer to limit movement.
With chain driven V8 camshafts we used a "button" on the front of the camshaft that held the camshaft back in close proximity to the thrust pad on the block. On some builds we even installed a thrust bearing behind the cam gear to prevent wear and prevent thrust from changing the camshaft position.