Am I understanding you correctly, you're doing all this because of the timing pointer??? None of that is necessary if that's the case. The pointer is a thin metal bracket that goes in with the timing cover bolts left and right of the balancer. It slides down over the top w/the balancer in place. But why do all that anyway, simply cut the left side off so that you only use existing bolts going into the timing cover. In other words you're only going to use the left side of the bracket where the pointer is. The right side does nothing.
Another nifty idea is simply use a chisel and tap a thin nick on the forward side of the transaxle vent, tap another chisel line at TDC on flywheel, another at 5, 10.15 degree increments & mark them accordingly using different color paint pens. Time from the engine bay then.
Many of that era cars like the Bora & other Maserati 4.7, 4.9's, E-Type Jags, & Countach that I've timed, they have inspection holes UNDER THE CAR of all places. From factory! Get 'cher timing light under there with a running engine!! Fun. Ferrari is a little different in that era, they time from above not below. They have 2 distributors like Lamborghini) with separate factory marks pre-cut into the flywheel so you time both banks one after another. Now do total timing with advance in, meaning someone in the car has to hold 2000 RPM while you time.
Thank God you have a Pantera. Those afore mentioned cars don't have the juice of the Cleveland... even with multiple overhead cams and multi carbs, six 2's...Webers on a V12 Lambo & Ferrari of the day. None of 'em ran w/a Pantera still won't.