Old Man with a Hat
FCBO Gold Member
- Oct 8, 2011
- Reaction score
I shared the idea to replace the Holley 4160 on a 440 once and was told it would be a downgrade to install any AVS carburetor.
A Holley 4160 when new did run better than an AVS Carter carburetor. It had a stronger accelerator pump shot and a richer off idle flow curve. The problem with the original 4160 Holley was that they didn't last more than a couple years of normal driving before giving driveability problems due to warped metering blocks sandwitched in the middle of the carburetor due to repeated heating and cooling cycles and poor casting materials used back then.
An original AVS carburetor ran OK when new but not as strongly as a Holley 4160 especially off the line acceleration.
The original AVS carburetors often displayed some stumbling on acceleration or sags when driven with a cold engine but they cleared up and drove smoothly once the heat crossover was heated up but not as well as a good 4160.
The AVS II carburetor is very similar to the original AVS carburetor in design but the Edelbrock version (AVS II) has better atomization of fuel at the nozzles even when cold and therefore runs just fine even without the intake manifold crossover heated up to help atomize the fuel. As such, the AVS II carburetors seem to match the performance of the original Holley 4160s even when cold and seem to have richer off idle and better WOT accelerations from stop than the original AVS carburetors in part because the AVS II seems richer in calibration than the original ones in the lower speed ranges.