Originally posted by techinspector1
You'd have to bore the 348 block 0.188" to fit a 409 piston. I don't think you could do it without hitting water. Here's a chart from Stan Weiss that will help you.........
http://users.erols.com/srweiss/tablersn.htm

I have read some chatter about using a 396/427 crank (3.766" stroke) or a 454 crank (4.000" stroke) by turning the main journal diameters down to the 348/409 size. The bore centers are the same on the two generations of engines, so the later crank will lay in the saddles.
yes it has been done one of my customers did the 4.000 stroke in a409 and the nose of the 454 needs to be turned down to and i think the rear main thrust needs work . if you have 348 i do not think you can make it a 409. i have rods and crank348. that is nice stuff if you need it crank is fresh turned and the rods are stock .