Use a table ban saw to hack off the 340 piston crown .

My understanding is 3.31" 340 stroke subtracted from 3.58" 360 stroke equals .27" added to the overall increase in thickness. Moparpush rod is 7.5" / SBC is 7.794- 7.8". So .30" is close to .27" I will use adjustable rockers to get it spot on. Not sure where you got the .80" figure. Gonna use the 0.080" head shim combined with standard 0.038" -.040" head gasket equals .120" to startwith and then I will check my dome and see were I stand. And go from there...pushrod length really needs measured when it's close to being assembled but you get the general idea...I hope, there's a lot of heklers and unbelievers out there.