Yeah, I've put a two speed engine on my 77 Puch Newport before (only to find out that the main bearings were bad in it, anyway). It was no problem to bolt up though, the only hard part was fitting the coil in there. on a stock two speed bike, the coil is mounted on the left side of the frame near the back tire, and on the single speed it's mounted under the tank part of the frame right next to the carb. I just put a small "L" bracket from the right intake bolt and I bolted the coil to that. It was kind of cramped, so it was bolted at a really weird angle (pointing up a little and off to the side a little). Just bolt it to one hole of the coil and tighten it all up in whatever position it fits. Other than that, everything bolts up just fine. I rode it around for about 10 minutes before I decided that the main bearings were too noisy and I put my old engine back in.