i am rebuilding a slant six and i need to know what size piston rings to get. where do i measure? the cylinder? the piston? or the ring?
the cylinder walls are in great condition so im not going to have them honed i would if i had more money but thats not gonna happen anytime soon. any help is appreciated. thanks

If the cylinder wall are good and everything is within specs, use the standard size rings. Be sure you de-glaze the cylinders with a 220 grit hone and get a good cross-hatch pattern. Make sure the lines intersect at about 60 degrees (about 10-12 stokes with a low speed drill). Otherwise its a wast of time putting new rings in used bores. The rings will not seal.

Measure the cylinder bores, just under the ridge at the top of the bore and also down low in the cylinder. Try to figure-out how much taper you have, top to bottom. More then .007 taper will be hard for the rings to seal.

The main reason to measure the cylinder is to be sure it has not been made oversize in it's life. I have seen oversize cylinders with factory oversize pistons, usually .010 over, right from the asembly line.
DD