Any recommendations for building a '73 340?

Build a stone stock short block. They had forged pistons and full floating connecting rods from the factory. They were a touch under 9:1 compression. Perfect for the street. Pump gas friendly. Go with the 2.02 valves. If this was something that I was doing and wanted your power level, I would not waste time with iron heads. I would choose an aluminum aftermarket head, have it prepped and ported to match the power I was looking for.

The Air Gap intake is a great choice coupled with a good set of headers. TTI and Dougs are two good choices. Most any of the modern camshafts will get you where you want to be power wise very easily. Something in the .550 lift range and around 240 or so duration @ .050 ground on a 108 LSA will get the job done. Some may say that's a little big, but instead of advancing it the recommended 4*, since you will have under 9:1, go 6* or even 8* advanced. Yes, with aluminum heads you can run more compression, but since it's a street motor, why? 1 point oc compression equals about 3% more power. Not worth having to run premium or having to worry about detonation in the hot summer months sitting in traffic at idle when the temp creeps up.

All of this of course is my opinion.