lanmanager,
'68 engines in a '67 boat? That's easy and in the motor / boat world not uncommon at all. Your Trojan was probably at the end of the 67' run when the motors became available. They simply put the 'new' motors in at time of delivery.
I've got a '32 Trojan Sportfisherman, with twin 351's. Be glad to trade you motors
Heck, I'd even trade you boats!
DV