I just finished converting my old 1990ish Diamondback to an electric bike using a Luna BBSHD kit and, 42 tooth front sprocket, and a 13.5ah 52V Dolphin battery pack.
I used one spacer on the chain side to move the BBSHD away from the frame a bit, This bike has a 73mm bottom bracket and I used the 68-73mm BBSHD kit.
Only two issues. The small spacers that Luna provides for the two smaller screws are too thick in width. They need to be thinner for clearance against the case otherwise the two screws can't be aligned to the threaded holes.
Second was the controller mount didn't really work to with my handlebars but I improvised.
Everything works well. I was averaging 30 mph on a flat road with the assist set to 6. I was out of gearing or I could have gone faster.
I have now nearly put on a 1000 miles in less than 2 months. I average 20 mph over 20 miles with plenty of charge left on my Dolphin Battery pack. Starting at a fully charged battery pack, I am usually at 50V when I get to work, or about 49V when I get home. Home is uphill from work.
I modified my bike with the following:
Luna CycleAmazon
Comment