318 + 904 question

Under no circumstances do you want to run it with the weights. Not only will it vibrate bad, it'll eventually wipe the engine out. May even take the front pump out in the trans. Do you have a pneumatic cut off tool? If so you can use it to carefully cut around the edges to get the weights off then use a hand grinder to smooth it down. You could do the whole thing with a hand grinder but I've found it easier to do it like I described.