I have seen some early '54 pre-production TBird brochures that show the 256 engine but the brochuress dated later in '54 show the 'new' 198 hp (292) engine in the images.
http://www.oldcarbrochures.com/stati...Folder-06.html
Even the earliest production '55 TBirds had the 292...
"For 1955, the first 1000 Dearborn-built Ford VINs - 100001 through 101000 - were reserved for the new Thunderbird. All of these cars had the same 292 cubic-inch V-8 engine (P) . . . "
http://www.tbird.info/first-1955-thunderbirds.htm
The one I have is slightly later than this earliest group, scheduled build date Nov. 9th of '54. I suspect one of the previous owners may have worn out / used up the original 292 engine.
Or... back-in-the-day the car was in a bad enough wreck to have the frame replaced. Maybe the original engine & transmission were 'borrowed' for another project at the time.
The '54 Merc 256 EBY engine in the car had a '57 tach drive distributor, '57 ECZ-B intake and an Autolite carb from an FE 390 when I got it. It barely ran at all, probably a vacuum leak from the mis-matched intake manifold.
List of Y-block engine block casting number prefixes by year...
http://www.ford-y-block.com/Block%20identification.htm
40 Deluxe yes it's odd they didn't list a 1:1 high gear.
I've seen the same transmission specs on at least one other website. Maybe they're just copying non-original info from each other???
On the left side of this linked '55 Thunderbird info page... (photo attached)
http://automotivemileposts.com/tbird/prod1955tbird.html
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