When I put the engine in the bike, the tank filler wasn't centered in the frame. Just didn't look right. So I relocated the mounting holes over 1" to get it where it needs to be.
Added a strip of steel, filled in the old holes with weld, and drilled new holes.
I Had to do that on one of my Ruttmans... You know what else works is a tank bracket from a 3hp ( the version with the gas tank mounted behind the engine) you flip it around and it lines up pretty good you just need to drill the center hole..