The kits come with everything you need. There are 2 parts you will take from your 2.8 HP engine and use on your 6.5 Clone.
The instructions are very good, and the quality of this kit is just outstanding. My son and I just finished swapping out the 2.8 engine and also hooking up the throttle assembly, using just basic tools.
He includes a great CD with pictures / instructions, including how to take the extra links out of the chain, which I was not sure about before seeing the instructions. Followed the instructions and it was no problem.
I hope this helps - and I would highly recommend purchasing the kit.