Beautiful job and it sounds like she's running clean.
My only question is, what valve springs are you running? If the're mild single's, I doubt you can turn enough rpm to max it out. If you're running the recommended double's (995's), I'd be a little concerned about popping a pushrod thru a stamped rocker at some point. But, maybe you used adjustable 273 pieces?
With that said, a stock 9.5 340 will make in the neighborhood of 240/250 hp. Being conservative, i'll give you 25hp for the cam, and 5/10hp for the Performer intake. So I end up in the 270/280hp range. Anything close to a real 300hp in my opinion, is gravy!
I doubt you plan on dynoing it, but that's cool with me.....I'd much prefer you get it installed and run her down the track. That's the real dyno. :D