1100 slabside - removing oil pump screws

[Dezza]

What is the best way to remove the three flanged cap head screws that hold the oil pump to the lower crankcase on an oil cooled motor? Mine is an 1100 slabside but I assume most oil coled engines are similar (unless the fasteners were upgraded). I have made an initial attempt with a 3/8 drive allen socket (good fit in head) with an extension but any more force and I can feel that the head of the screw is going to mash. I do not want to go in like a bull in a china shop as if these get rounded they are going to be a pig to get out. I was thinking of heating the section of the case where they thread into first, then using an impact gun but if anyone knows of a consistent way of removing these screws effectively then I would appreciate it as these three fasteners seem to be made from hardered cheese

[Gixer1460]

Add a 3/8 to 1/2" adapter to the 3/8 hex socket and use a 1/2" impact driver - usually a good clout with an engineering adaption tool will shock them free. I've never used heat on anything.

[Dezza]

Ok, I'll try the 1/2" drive impact driver