[chiphead]

Lightning round:

1: Yes. If its listed as a pontiac balancer and has 4 bolts, its likely same as stock 68-newer dimensions

2: Don't know

3: Not sure about the pulley mounting face on the balancer. You'd have to compare the overall distance of the two balancers themselves.

4: Don't know.

5: I think the water pump pulley for '67, '68 and '69 with short 4" 11 bolt pump has the same offset. Diameters were different depending on AC or not.

6: Don't know. Very doubtful

7: The same alt/PS accy brackets were used for LeMans/GTO from '67-70. Not sure about big car.

8: Cast aluminum PS/ALT bracket is the same '67-70. Not sure about '65-66. or big car.

I went through this on my '67 Lemans/GTO. The 11 bolt water pump and 4 bolt balancer is worth the changeover. The '68 system still uses the 8 bolt pump, it sucks.
Run a '69 or '70 system for a GTO if that'll work in the big car. There is a short fan clutch that will position the fan in the correct place in the shroud.