rearenginekarts.com

I ressurected an old D44/55 saw a while back. Nothing special, its a later model that looks like a typical early kart motor. Looked like a Mc10 block with excption to it only having a 2" bore and 1 3/8" stroke. It had been robbed of vital parts unique to the Mc10 motors. So I used more common saw parts to replace what was stolen. I recently acquired two more leftover 55 models. Here are the serial numbers of all three:
86
7362
c16792

They sold tons of these first of a new line for McCulloch. The D44/55 models ran from September 1956 thru 1958, even after newer models became available.

What I noticed is the first two with low serial numbers have factory squared exhaust ports. The cylinders are a weaker casting and a little different than later saw and kart style blocks. The last saw, even tho same model is a newer kart style casting and only has the exhaust ports drilled, but not machined square.

You can see the shape of cylinder and squared exhaust ports on early bolck. McCulloch dropped this early in production of this model, two years before they introduced the Mc10. Then opted for it again later in 1962 on the super models of both kart and saw motors. Another thing I noticed is the pistons used on these early saw blocks have bronze bushings instead of needle bearings for the pin to ride on.

BTW, thanks to a few good guys here that have offered their leftover parts these saws will be complete and running again. They will become look alike Super 55's. I hate to see good old saws die without a final cutting chance.

Interesting ol mate i missed knowing about them

Judging from the balanced flywheel, modified exhaust ports, and low serial number it could well be a former McCulloch dealer demonstrator saw, kind of similar to say a pre production Corvette that Chevrolet would loan to the a car magazine for a road test. Not exactly what you actually get when you buy one from a dealer.
Here are a couple of old pictures from McCulloch's office, check out the goose.

I had considered that, but the second saw I have with serial number 7362 is identical. Its only on these earlier castings that the ports are squared. I figured the same model with newer casting and shear numbers being produced, the power loss if any was not substaitial enough over cost savings of eliminating one more time consuming machine operation not to square them. That poor old flying goose got shot down shortly after these smaller models made their debut.