Holley Avenger or 3310 ?

[68Stepbed]

Originally Posted by chevy72blu

4150's are absolutely vacuum secondary carbs, and I am not sure about others - but my Vette-correct 780 had a choke.

Actually 4150's have both vacuum and mechanical secondaries. The 4150 series have both front and rear metering blocks. The 4160's have a metering block on the primary and a metering plate for the secondaries. The metering plates are not adjustable. The only difference between mechanical and vacuum secondaries metering blocks is vacuum secondary blocks don't have power valves and accelerator pumps.

Also, vacuum secondary carbs can NOT be converted to mechanical seconday and vice-versa. The vacuum secondary main bodies have vacuum ports with a check ball.

Originally Posted by 70c10

Why not try a Demon?

Those rock! I tried one on my truck once. I sent it back because I couldn't get a smooth idle. I found out later it just needed a simple adjustment.