Yes I broke it in as per manufactures instructions. Put about 8 flights on it running a rich setting. The last couple of flights you could tell it was starting to get broke in
I ended up putting the Magnum on my clipped wing Cub, the bolts holes were them same as my ST GS40.
I have a Saito 56 & 72 and will probably mount the 56 on the 4 * when it`s done and put the 72 on my Ultimate 40.