item   281051675925 

just spotted the above item on e-bay has the choke built into the i/l manifold may be of interest to someone?

stuey

Interesting! Thanks, Ted.

I'm often surprised at the re-engineering that is done during the life cycle of a product. I would have expected the '54 Merc 256 and the '55 Ford 272, 'Bird and Mercury 292 intakes to all be the same. The casting number change suggests that something like intake runner sand cores were changed. Likely, there was ongoing dyno testing of the engine as cubic inch displacement was increased. That said, I'm disappointed that the rockerarm assembly oil deflector trays (?) and the timing set drip tray were eliminated before the (?) '57 model year as 'not being necessary' or at least not being cost effective.

I'm still puzzled that the late 292 truck engines with the forged cranks used a different connecting rod length than had been used for so many years in the 239, 256, 272, and 292s. Additionally, rather than using the 312 connecting rod which was the length they went to for the HD 292 truck engine, they designed a new beefier connecting rod. $$$ to do that. Additionally, opting to use a shorter connecting rod for the HD 292 truck engine required a change in the location of the piston pin. Again, $$$ to do that. I assume that the decision to use the shorter connecting rod for the HD 292 truck engine had something to do with a mathematical calculation regarding piston dwell time at TDC or torque at some particular engine RPM. I'm guessing on this as my engineering insight is rudimentary at best!

NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

The ’54 heads had smaller ports which simply necessitated a smaller port intake.  Hence the manifold casting change for the ’55 heads when they came out.

The 292 truck engines came with two different rod lengths.  The higher compression ratio trucks came with the longer 292 rod while the lower compression truck engines came with the shorter 312 length rod.  This is excluding the engines that came with the 471 heads as most of those had the longer rod lengths regardless.  Fords quick solution to lowering the compression ratio where required was simply put the 312 length rod in the 292 engines while using the same piston for each.  The shorter ECZ rod evolved into the stronger C1TE rod while the longer EBU rod evolved into the C2AE rod.  So that makes a total of four different rod forgings out there but still only the two basic rod lengths.  If I need to use a particular oem rod for a Y build, then my preference is with the C2AE rod.

Lorena, Texas (South of Waco)