Mike , I thought about the same thing when I did my 66-e blaster , and this is as far as I got, Mostly due to lack of interest after completing the engine install , I may finish it later . anyways : here is a 155 pump that I cant remember what its out of , I installed a standard WB-1 shaft and had to shorten the pump case in order to make the shaft long enough to reach the midshaft , If i remember correctly You will need a 155 shoe but thats where I stopped , those bolts with the nuts for shims are just holding the pump together , the rear pump mounting ears were too tall so I ground them down '' caveman style '' to get them out of the way and then drilled mounting holes in the barstock , also you will have to change your cooling feed so its closer to the pump or itwont clear the hull , you also must gring down the flanges as you can see in front of the weld and behind the weld , I know its a little neandathol looking but it is my prototype and I had no help or outside Ideas when i did this. I dont know how much you will gain due to the pump tunnel being sized for a 144 mm pump , I think you may gain some but not the full capability of the 155 tunnel in the gp1200 so it may choke down the 155 pump ?? I dont know Im just a..... caveman LOL ! . FWIW
