This is a 72 El Camino 350/TH350.
I get this whining noise that sounds somewhat like a slipping belt but more metallic, only when I jump on it from a stop. Does not do it when I mash the gas in park.Any suggestions on where to start looking for problem? Could it be water or power steering pump? Has new flywheel (replaced due to starter noise, had chipped teeth and two bolts loose) but that had no affect on this noise.

Could be your fan hitting the shroud, if you've got a broken motor mount.

I hadn't thought about motor mounts, that's
a good possibility. Will check it out. Thanks.

No time to check motor mounts, but popped out and inspected the shrowd. It has wide grooves in it, the upper/passenger side, the fan has clearly been hitting it. Can I change those motor mounts by jacking with a block of wood under the pan?