this is where using a non recomended type engine starts to add up,the iso smooth mount thats provided is set up for a OS Fx or AX 46 so like your finding out different mfg. or even types have mounting holes, ears,and needle valve positions, that vary in size,when I mounted the OS 61fx in my Nextar I had to redrill for a different mount,new throttle pushrod, and alter the fuse to clear the needle valve,I had stripped the covering so it was just a little dremmel work and it was done.
I am sure there are many who have used other engines with little effort and will chime in on there expierences installing there favorite engine,I only have OS glow engines so thats where the bulk of my expierence lies.