I looked at it again today and you are right. I'm thinking that they revearsed the exhaust manifolds for the dyno hook up.

That's does not appear to be a cross over header as the flange mount is turned down. I thought it was a right hand header mounted on the left side of the engine?

56 VIC  Gene Stoehr Sr.

The left side exhaust manifold exits in the front of the engine. Looks like  '54 or '55 with single exhaust. That would not be a 312. It is a Y block though. I thought it was interesting.

Page 75 Is that a 312Y-Block Mercury that Vic Jr. has on the dyno? I am surprised that this picture made it's way into his tribute article.

56 VIC  Gene Stoehr Sr.