will this cam fit it 318

I would start looking around for a 360 bigtommy. You would be better off in the long run and have a good engine to start with if you decide to stroke it some day. See the 360 has a longer stroke crank than the 318 crank so that's automatically better. It makes more torque. I ditched a 273 for a 360 so I can tell you from experience. They have totally different personalities.

Take your time and look around to find one. You will be miles ahead towards the 30 MPH burnouts.