Looking for a manual place diverter control, preferably stringer mount and cable if possible.

Located in SW Washington State

So I am installing a new 460 canton oil pa n 18-760 with the 18-761 pickup. The support bracket for the pickup appears to mount on the center main cap bolt but the mounting hole is too small? Also the clearance to the bottom of the pan appears to measure about 3/4" which seems like too much.
Should i just drill out mounting hole or am I missing something? Would it be ok supported off the oil pump and no center support?
Tha ks

So I pulled my two fuel tanks after going through several inline filters and still getting crap. Tanks were held in by some kind of spray foam almost like "Great stuff" foam. I'm thinking someone did this as a quick fix? Or is there some kind of product designed for mounting fuel tanks this way? The tanks are rectangle galvanized steel and I can see where it looks like they used to be secured with fiberglass on the front and towards the back on the bottom.
What would be the best way to reinstall these? Should I fiberglass them in or build some kind of a mount / strap?

Thanks

Just got my first boat spending some time getting it set up. 1976 Eliminator  460 Berkeley Jet. Supposedly has a little head work and a mild cam. Couple questions.
Just installed a weiand stealth intake and supposedly has a 750 carb. Would I be better off with a 850? Should I use a spacer?
Also I want to install a water pressure gauge will fuel pressure gauge work for water? Has anybody drilled and tapped a gauge Outlet on there water Outlet housing? Or should it be installed elsewhere?
Thanks