Piston Choice on 318

Well I did not listen and swap some 308 high swirl 360 heads with the 2.02 intake valves on my 318. Had the chambers milled to 63cc's.

My motor makes more power everywhere it seems like and I rev it no higher than 6000 rpms but it does have 3.91 gears.

I hear those hyper pistons crack easy if the motor pings but nobody makes a high compression forged piston for a 318??