383...diff. year question...

Theoretically, milling .090 off of the block would get that compression back. Then you will have to change pushrods, header alignment changes, bolt lineup with the intake will be way off, valve to piston clearance becomes much less, narrowing camshaft choice, vavletrain geometry changes. More, and worse, changes if you try to take it all off the heads.
If you want ten to one, buy ten to one pistons, dont try to make 8 1/2 pistons into something they arent.