This maybe a dumb question but why didn't Chevy ever fool around with the idea of distributor in the front like a Ford. I just think that you would have much more clearance in the back especially when your trying to clear a firewall.
The real answer is that GM didn't care whether or not you can fit their motor in another car.

Chevy did change to a front-mounted, cam-drive distributor - on the LT-1 motor.