[Scrubcadet10]

45psi is pretty low... 50 PSI is what i would call "bare minimum".
could be a valve not closing all the way, as that tends to happen with L head engines, the valve lash gets tighter and can eventually hold a valve open.

 

[Scrubcadet10]

45 psi is even low for an engine with a Decomp on the camshaft.

 

[Scrubcadet10]

there may be 3 holes in in the bowl screw (#15), make sure they are clear, the idle adjustment screw on the side may need tweaked with, (#17), screw it in until fully seated, not tight, just snug, and back it out about 1/4 turn at a time and try to start each time.

 

[Scrubcadet10]

I have a set of brushes like those, they work great!
some people use torch tip cleaners, but the tip cleaners are much more abrasive and rigid than the the carb brushes and if you aren't careful you can take material out and suddenly your engine is running too rich.