Hmmmmm...
The valve covers Oldmics and Slick56 refer to would be striking, Ted. Modifying them for use in the Engine Masters Competition may not agree with the budget or, more significantly, the comments you may wish them to evoke when viewed by observers of the event.
IF I'm understanding correctly, Lindsay's aluminum casting are aftermarket custom and while 'attractive and distinctive', they are unlike anything seen in that era on the 'small' species y-block Mercs. More specifically... yes, they're being produced now, BUT they are not what was used on production Mercury 256, 292, or 312 y-blocks of the 1954 - 1960 era.
Consider using original type steel valve covers that have the embossed Mercury letters, modify them as needed for the competition, and then having them chrome plated to make them 'distinctive' but also truly relate-able to the earlier time. -This would be in keeping with what Ted did in 2010 when '55-'57 'Bird-only valve covers were used, but they had been made strikingly distinctive by their being painting black.
Ted indicates that Kasse's valve covers will be original Ford type as were original (as an option) on the '55 -'57 'Birds only. These will be original AND speak to the era of the engine. While there will be much to the Eaton and Kasse's entries that will not be 'of-the-era', perhaps having original style valve covers, an identifiable moniker for the engine, would be a plus for viewers' to identify with the history of the engine entered in the competition. Back in the '50s, there was significant competition between the Ford and Mercury divisions...
I do LIKE Lindsay's valve covers. I just wonder IF they would be the 'best flag' for the Eaton entry to carry for this competition. Similarly, to stay in identify-able character, perhaps Ted's engine entry should be painted a y-block Mercury period color, too. Weren't '56 Merc 312s a gold color? -Food for thought...
Best Wishes to all involved in the EMC entry.
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York