Small roots blower for smallblock

A boost gauge is mandatory or at least one temporarily hooked up. Each individual application is different. Stock engines will be fine in the 5PSI range. I'm gonna bet you're going to be making around 5PSI. Run it the way it is. Run a tighter gap on the spark plugs.
The head gasket is the weakest link.......
I run SCE copper head gaskets, my heads are O-Ringed and I got receiver grooves cut into the block.
With boost I would recommend 360° main bearings, to give full time oiling of the rod bearings. But, in your application I wouldn't loose sleep over it.