Omc cross flow exhaust

So here's a question for the old school omc racers, I've got a bunch of omc 4 cylinder blocks and I'd like to experiment wt megaphone exhaust. I've seen a few pics of this done, and I'm wondering if it works wt these motors. Also if one of u out there has done this modification what would the pipe deminions be? I'm a machinist by trade so doing the work is not a problem,how ever I don't have the knowledge u guys do. I love the pipes on the mercs but I'm a omc man. Any insight would be appreciated. Thanks