Carb sizing question

[boostin20]

I bought a 72 c10 last month and just put in a 350 with a RV cam. With the cam, it's only 20 or so horsepower over stock. A quadrajet 4bbl came on the old engine. I don't know what size it is, and I won't be around the truck to look until tomorrow. I put the old carb on the new engine and adjusted it at idle. When I open up 4 barrels (stomp the gas), the truck immediately falls on its face until I let off the pedal. My two questions are this:

1. What is the best size 4bbl carb for an engine with no more than 300hp?
2. What do I have to do (if you think I don't need a new carb) to resolve the falling on its face issue when the other 2 barrels open?

[Pyrotechnic]

I had this issue when I upgraded the stock cam in a my motor. The issue is not carb airflow capacity, the issue is that your primary fuel metering is too lean. You will need to find a larger jet, or get a small drill bit set and drill out the one you have.

Also, be aware that these cams will like more timing than a stock cam will. About 34 total is a good place to start. Setting your timing to stock specs will make the motor run badly.

The average Q-Jet will flow 750 CFM which is good even for a mild big block.

[Sport/Truck]

Originally Posted by Pyrotechnic

The average Q-Jet will flow 750 CFM which is good even for a mild big block.

Some will argue it's too big for a SBC...
s/t