I didn't think a 289 could be bored and punched to a 331. If I remember right, the 289 has a shorter deck height than a 302W. Do your pistons have any valve reliefs cut? What size combustion chamber size? Rocker ratio? Total cam lift? Is this a high compression engine?

Also, why not build a 5.0 roller motor? Better valve train, more parts, probably easier/cheaper to stroke...