Spark Plug Help

got the autolite 104 @ .033

302 ci
heads gt40p milled 30/1000

got nice tan on most,
small black strips on a couple(1/4 side of insulator)
many of the center electrodes look like the end of a toothpick, sharp tappering down.
I know the new ones are flat and round, how bad is that??
Been having a sputter at 3000-3500 rpm, is it being blown out??
no codes

took me a while to find more info on the smaller diameter electrode, but from what i read it seems they will ignite easier and can even be in the 17:1 range and cause misfires on higher compression engines, so i may have solved it. ...try and change the plugs tomorrow.