McCulloch D-44, D-44A, Super 44, Super 55, D-30 - D-36..... 1957-58
Mc 1-40, 1-42, 1-45, 1-50, 1-60,1-62, 1-80,1-81, 1-82, 1-85.

These saws has been used to recreate some of the very early Kart Engines, and have a removable head and some have the outer housing for the points and condensor.
Plus it's fan / cylinder housing is the same as the earlier Karts used.
The crank is tapered.
The D-30 and D-36 have the points moved to under the flywheel.

Mac 15. 80cc 4.9 cu-in

Possibly another saw of value in it's ressemblance to the Mc 49, 49e and 49 M/C.
It has the fixed head BUT the Mac 15 has the stepped crank.

Mc 790 @ 103cc to Mac 70 clone.

The correct block for the MC-10 is a1-70/1-80 powerhead.
1-70s are direct drive and 1-80s are gear drive.
The 1-70/80 was the last model produced that used pushrod operated points.
The other two most similar powerheads are the Super 44A and the Super 55A.
According to Jim Yamane his first dual engine rig was powered by Super 55As. Later he used Mc-10s when he became the first World Champion Karter at Nassau.
As for the later blocks, 1-71 1-72 etc. they have the larger od PTO bearing ala Mc-20, 30, 40, etc. but will work. Remember also that those powerheads did not have the pushrod operated points so the crankshafts are different.
The D-44/M55 fan housing and shroud interchange with a number of saws such as the Super44, Super 44A, Super 55A and some others.
All the Mc-10s I've seen came with the tag riveted to the head shroud originally. Many of the Mc-10 shrouds were cut for header clearence which elimanted the tag. I just had to cut up 3 of them myself a while back.
Mcculloch called the flywheel cover a "fan housing" and the Mc-5 fan housing appears to have been used on a 1-40, 1-50, and 1-60 saw.
There are other items unique to the Mc-10 kart motors, one is the number of different styles of point pushrods they used. Maverick spark was common on Mc-10s. Tom