ATC 70 Oil Pump Drive Sprocket removal?

[GTO]

I need to replace my 70's oil pump drive sprocket.
Can I remove it without splitting the crankcase?
I presume the oil pump drive shaft end is threaded where the sprocket goes on?

[tblumer]

Yes, lefty loosey.

[GTO]

Do I need to hold the sprocket some how and try and unscrew the shaft from the oil pump side?