Hello, Mike.
The 740 and the 747 are both "Medium" length drawbar couplers. It's not the length of the drawbar that's at issue, it's the height. MTH builds their truck-coupler sets with the drawbar at approximately the correct height which is swell until you want to replace The Claw with a Kadee. In a perfect world, either Kadee, MTH or both would make a replacement drawbar with a built-in Kadee draft gear box but it hasn't happened, yet. If you bolt a 740 on top of an MTH drawbar it's too high and the Kadee drawbar will hit the underside of the carbody; if you bolt it to the bottom of the MTH drawbar it's too low; therefore, an offset is required and the 747 is the closest thing available.
Looking at my own photos, it now occurs to me that an MTH "full height" dummy coupler drawbar might be adapted to the purpose. If the coupler head was sawn off at the proper length and then the drawbar slotted at the correct height, perhaps a Kadee 740 drawbar might be inserted in the slot and bolted in place. Thanks for the idea! Having decided to re-truck a 21" K-line Super Dome with MTH three axle trucks and I will give it a try.
Perhaps Ron has some ideas on the subject.
