ATM/Holley verses Carter 625 AFB
I'm not interested in participating in the carb science pissing match- but I will chime in that I have 2 seasons (probably 60-70) 1/4 mile passes running a pair of 800 AVS2s on my 440. I tune with an AFR gauge, vacuum gauge mounted on the dash connected to manifold vac, and reading spark plugs. I keep spreadsheets of changes and time slip performance. At the end of the 2023 season, I switched over to a pair of 650 DP ATM XRB series that they prepped for sideways dual quad service. Unfortunately, I only got 1 clean pass on the ATMs in October 2023, and my ET, mph, and 60ft were a little better than my best with the pair of Ebrocks. The next pass, I tossed a rocker arm and bent a pushrod, and that ended my season and I did a tear down and rebuild. (I suspect that my first pass might have had #6 cylinder rocker adjuster loose - and they let go second pass)
When rebuilding, I threw a stroker kit into the 440, so I'm now @ 505". I'm going to put the 2 ATM 650s back on it to start the dial-in process over again.
The main reason I switched from the Ebrocks to the Holley style carbs is the ease of adjust-ability with air bleeds, and availability of jets, power valves etc. We do drag-n-drives with this car, and we have tuned ourselves through a ****-ton of elevation changes, especially on Rocky Mountain Race week. The Holley Style is just easier and I think you can get the max out of them with less effort. I will save the AVS2s for a street cruiser - in that purpose, they are fine.
I'm not interested in participating in the carb science pissing match- but I will chime in that I have 2 seasons (probably 60-70) 1/4 mile passes running a pair of 800 AVS2s on my 440. I tune with an AFR gauge, vacuum gauge mounted on the dash connected to manifold vac, and reading spark plugs. I keep spreadsheets of changes and time slip performance. At the end of the 2023 season, I switched over to a pair of 650 DP ATM XRB series that they prepped for sideways dual quad service. Unfortunately, I only got 1 clean pass on the ATMs in October 2023, and my ET, mph, and 60ft were a little better than my best with the pair of Ebrocks. The next pass, I tossed a rocker arm and bent a pushrod, and that ended my season and I did a tear down and rebuild. (I suspect that my first pass might have had #6 cylinder rocker adjuster loose - and they let go second pass)
When rebuilding, I threw a stroker kit into the 440, so I'm now @ 505". I'm going to put the 2 ATM 650s back on it to start the dial-in process over again.
The main reason I switched from the Ebrocks to the Holley style carbs is the ease of adjust-ability with air bleeds, and availability of jets, power valves etc. We do drag-n-drives with this car, and we have tuned ourselves through a ****-ton of elevation changes, especially on Rocky Mountain Race week. The Holley Style is just easier and I think you can get the max out of them with less effort. I will save the AVS2s for a street cruiser - in that purpose, they are fine.
