I did this back in the early 80s when I rebuilt the ole 348 for the Impala. As the "W" motor fans know the deck angle to the cylinder bore for these engines isn't perpendicular to one another. So how does one install the pistons into the cylinders after a rebuild? >A< You can run down to your favorite AZ and purchase a 348/409 piston ring compressor. Ya, sure.. >B< Get a few of your favorite buddies over for a install party with a half dozen flat blade screw drivers. I don't recomend this! >C< Try it by yourself with the kids outta shouting range. Or >D< Takes a little preplannning but I used a piece of black pipe and bored it on a lathe to a couple of thousands under my finished bore diameter. Squared up one side to the bore and milled the other to the proper 17 degree angle of the deck. Use a standard piston ring compressor on the square side. Worked like a champ. I'm sure there are other ways but it's how I skinned the cat.