If you have the time to do this, it will definitely work; I unstuck an old Chrysler flathead that had been stuck for many years this way. I learned this from an old shadetree mechanic way back in the days when there were more shade trees than there are now. With the V-8, if it is on a stand, it will be easier to do, because you need to get the cylinders vertical.

Mix some cheap motor oil and Marvels and/or diesel, 50/50; you will need about twelve to fifteen quarts of each, so the diesel is a bit cheaper. With the engine on the stand, turn it so one bank of cylinders is straight up and down, pull the spark plugs, fill all of the cylinders with the mix, and re-install the old plugs. Do the same on the other bank, then roll it up straight, and fill it full with as much of the mix as you can get into it. Let it sit for a week or two, at least; longer is better. When you are ready to go at it, again, put a big drip pan or some other means of catching the oil, under the thing, pull all of the spark plugs out, and start trying to turn it by hand. Once it is free, drain all of the stuff out of it well, refill it to normal with fresh oil, rotate it a few times, prime the oil system with a drill motor ( the adapters to do this with a Chevy are usually available for a fair price at most good speed shops), and proceed as you normally would.

It seems to be overkill, but all of the engines I have ever done this to have survived very well. Of course, you could just put it on a stand, and pull it apart, and re assemble it, or even rebuild it, and you would have no question about it's condition.