That's the same manifold as was used on the 292 (200hp) engine in 1969, and that engine used a 4 bbl quadrajet carb. There's no real point in putting a bigger carb on. That engine (your 165) will demand no more than about 280 CFM (even at 4500rpm). Putting a 650 CFM carb (for example) on will not produce a single more horsepower. Remember, a carb supplies what's demanded (sucked in), it doesn't force anything in, so having a bigger carb on may kill the low end torque (due to large venturi size the air flow is slower, thus making it harder to control the fuel mixture at very low engine speeds)...
Chris.......
