349 CI on the cheap

What are the valve sizes, and the cam used?
As for which cycle it occurs at will depend on the cam and how it's been ground. The cam it self creates this problem with a 0 deck piston. Most aftermarket pistons have the valve reliefs already in them and deep enough for a large cam.

As for the piston and cam comming together I would say 0 deck and 240 or greater duration @ .050 and less than 108 centerlines.