I put a 2 barrel vacuum secondary of a 1980's honda 1600 on my '47 216. These are a Keihin carb and the secondary venturi is about the same as the Chev. The primary is a lot smaller. The truck has the cab off right now so I cant drive it. But idling and running so far look very promising.
The float level is adjustable and I had to lower it until the main jet on the primary venturi stopped flowing at idle. Then I could adjust the idle mix and speed for a nice 4-500 rpm idle.
This is not a conversion for power although the total flow is probably 10% more than the rochester original. I expect it will go better and use way less gas. It appears to run very clean right now. I wont know how good until I can hit the road.
I had to make a manifold adaptor and rejig the throttle linkage.
Float level, within linits, doesnt affect the volume of fuel flowed and I expect it to run well. The NZ Hondas had no emmissions gear and this helps. I bought two for $39 each, mint condition.
So you may find a good alternative carb off some vehicle you were not expecting. The Jap Keihins were great carbs.
