Charlie,
The Pontiac Engines for the most part used one chain from a Second Camshaft Gear to drive both of the OHC camshaft gears. The Crankshaft had the normal timing chain drive driving a cam with no lobes that drove the normal pontiac oil pump.
Some engines had the chain drive in front and some had the cam with no lobes driving the oil pump and a gear/ cogged belt drive system on the flywheel side of the engine.
(see link:
http://www.wallaceracing.com/ohc-v8-cover.html
The engine on the cover of Hot Rod next to Mr Mackellar was a DOHC (4 cam) engine with the drive in the front.
The engine on the cover of Hot Rod at the right bottom had the cam drive located on the rear of the engine and was a SOHC (2 cam) engine.
Hope that helps Charlie. Rear drive cam used a timing belt.
Brabham engine used a chain drive.
Tom V.