Delray, go get an Olds book man. As for the 307, its possible to put any SBO heads on it with the exception of 206/307 7A(85-newer) without changing the intake. As for your flow question, it would indeed breathe better. However, this effect would be immediatly canceled out by low compression. Unless you plan to shave the heads to re-gain compression, it wont help. Your best option for a 307 is a Cam, a good exhaust, and a set of 442 307 heads. Remember that in 85 Oldsmobile went swirl port, and these heads are just plain restictive. I believe that the Hurst olds from 83 are larger valved heads, so this represents an option. If you dont like this, just have your current heads checked for cracks/stress and have them mached for larger valves. Hoped this helps. The 307 has a lot of potential if you have the time