Yes there is a difference. I had to do this when I put my LA 360 in my satellite with a 904. In order to run your 904 with the 318's nuetral balance converter behind your 360 you need to pick up a weighted flexplate from B&M or an equivalent. The one I picked up had 727 & 904 pattern on it so don't be scared away from one that's has both if you come across it.

The second option is to use your nuetral balanced flexplate and a weighted converter with the 904.

I chose the aftermarket flexplate and i'm glad I did. It's much stronger than a stock flexplate and I never had to remove the trans or torque converter from the car during the swap, and I didn't lose a drop of fluid either.