I am having similar issues. I have an SXI Pro and want to move my Solas pump 2" towards the rear. I found out this weekend that the prop sits about 1/2" further back in the solas pump vs. the stock pump. I have an extended SXR shaft intended for use with a setback mag pump in an SXR (+3" over sxi pro shaft), but am facing the same issue with the shaft noting being the correct diameter for the through hull bearing. I plan to have the shaft spray welded and turned down to the proper diameter.