You would want a cast aluminum cover, maybe a Blue Thunder cover, or a Dove cover, or an old marine cover. Talk to Summers and they'll machine it to accept one of their drives (which are sold separately from the SBC and BBC covers they show on their website). Or, find a drive on your own and machine a cover if you have the contacts or resources.
Summers Bros isn't the only company that makes separate drive units for cam-drive applications...
Summers Bros/