[Sam Mac]

This is a list of the parts you will need to do the CH swap. This is what is used on an 1864 and it makes the swap almost a bolt in. Try the sponsors for the parts.

1 603-0025 Plate Assy, Engine Mounting nice to have but you can use the plate you have.
2 736-0185 Flat Wash, .375 x .738 x .063

3 710-3118 Bolt, Patch, 3/8-16 x 1.0 Lg

4 750-3009 SPACER (4) you will need these

5 710-3124 Bolt, Patch, 3/8-16 x 2.25 Lg

6 751-3110 Muffler you will need this

7 711-3006 Stud, 7/16-14 UNC-2A Thd you will need this

8 736-3086 Washer, External Lock, .45 X.75 x .03 Thk

9 703-2176 DUCTING-MUFFLER you will need this

10 736-3024 Washer, Flat, .47 x .750 x .0605 Thk

11 712-3019 Hex Nut, 7/16-14

12 703-2177 Duct, Engine

13 736-0142 Flat Washer, .281 x .50 x .063

14 710-3209 Bolt, Hex, M6-1.0 x 10 MM Lg GR5

15 710-0224 Hex Washer Screw, #10-16 x 0.500

As far as the drive shaft I would cut the shaft from the 2185 and slip it over the existing shaft for your 682 get the length adjusted to whatever it needs to be then drill a ¼” hole through it and put a spirol pin in it, maybe even two just to be safe. That way you don’t have to go out and buy an adapter to bolt the shaft to the back of the engine. The 2000 series drive couplers are pretty bullet proof and they don’t need any maintenance.