weber cfm flow rates

[sen2two]

Heres some i found, not sure of the accuracy... but seem reliable.



Source: JayCee Ent./Perf.Tech- flowed on Superflow 600 @25" water

Weber 48mm IDA w/44 venturi-348cfm (per venturi)
Weber 51.5mm IDA w/47.5 venturi-395cfm (per venturi)
JayCee 62mm /55 venturi -633cfm (per venturi)



with 20" water

Holley 1150 Dominator (4 barrel) 1180cfm (est.) total
Weber 48mm IDA w/44 venturi-311cfm (per venturi)
Weber 51.5mm IDA w/47.5 venturi-353cfm (per venturi)
JayCee 62mm /55 venturi -565cfm (per venturi)




Source: Gene Berg Ent. no flow specs given

Weber 48mm IDA 40mm venturi-561 per carb
Weber 48mm IDA 42mm venturi-583 per carb


Source: CB Performance 1991 catalog- no flow specs or venturi sizes
I assume these numbers are @28" H2O per venturi

Dell'Orto 48mm DRLA 388.5cfm
Weber 48mm IDA 372.1cfm
Dell'Orto 45mm DRLA 329.3cfm
Weber 44mm IDF 292.3cfm
Dell'Orto 40mm DRLA 266.4cfm
Weber 40mm IDF 212.8cfm
Dell'Orto 36mm 205.8cfm

[sen2two]

Now i posted that for reference for my question. Im building an old school twin dizzy 12a with a moderate to large sized peripheral port. I have a Holley 465 that i was wanting to use, but i also have a holley 600, wich is now seeming to be the better choice.

I have seen time and time again, people try and succeed on getting a 600 to run good on a 12a, but a 465 still seems to be the better choice. But these are on street and bridge ports. Im thinking a 465 might be to small for a PP if a 48mm weber can choke a PP and having well over 100cfm more flow.

So would i be better off using the holley 600 in this case? or porting and modifying the 465 some?

About how much cfm does a PP need? This might help me in picking a carb...

[PercentSevenC]

You're going to run a 4-barrel on a PP? If I remember right, peejay didn't like the results when he tried that.

I'd run the 600 with separated runners between the two rotors (i.e. no plenum).

[sen2two]

I have been trying to find a decent 48mm weber (or larger) but they are hard to come by, and the prices are only going up. But i do have these two holleys. So im goin to try them out.

I wanna see if i can port out/modify the 465 to flow better since its in much better shape than my old crappy 600 wich will need some work.

[PercentSevenC]

Really? You can buy them brand new, DCO, IDA, or IDF. You can even get 55 DCOs from Weber these days. Now that would be one kick-ass setup: 55 DCO with a non-wraparound manifold on a peripheral port.

I can understand not wanting to pay 500 bucks for a new one, but I think it would be worth it.

[sen2two]

ok, so i picked up a 48 dhla weber (used). Im thinking of swapping to a 44 venturi. that will get me inbetween 600-650 cfm after i polish and clean up the butterflys and shaft.

anything else i should do to the weber? or not do?