Rochester 2bbl help

DanBar · 08-16-2025, 05:27 PM

There are a few 1.375 venturi Roch. 2 bbl carbs out there but I have only found 1.. I do know that the carb NHRA list for that combo 7029113 is a holy grail 1.375 venturi 1.6875 throttle blade set up. This is the same venturi throttle bore sizing of a holley 500 cfm carb. I have one, and I have not given up hopes of building a 1970 version of the 350 250 hp combo. That 69 and 70 350/250 combo are the only ones NHRA lists with that venturi size. As someone stated a 1/2" open end wrench will just fit over the dividing wall between the 2 throttle bores. it is a quick way to check if the carb truly is a 1.375 venturi without disassembly to measure. the two small orifices under the baffle held in place by the front booster cluster screws are the hi speed air bleed. they allow more or less air into the fuel well. the drops tubes in the fuel wells can have different size and number of holes. this is the emulsification circuit. the accel pump discharge are the 2 hole on the face of the cluster between the booster they are drill at an angle to shoot into the throttle bores. That is most of my knowledge of the Rochester 2VG other then a lot of builder drill and re tap the main jet holes to take Holley main jets and start in the mid 60's for jets. Ask any question Iwill pass the knowledge if I have it.

08-16-2025, 05:27 PM	#5
DanBar Junior Member Join Date: Jan 2022 Location: summer shade ,ky Posts: 19 Likes: 22 Liked 12 Times in 6 Posts	Re: Rochester 2bbl help There are a few 1.375 venturi Roch. 2 bbl carbs out there but I have only found 1.. I do know that the carb NHRA list for that combo 7029113 is a holy grail 1.375 venturi 1.6875 throttle blade set up. This is the same venturi throttle bore sizing of a holley 500 cfm carb. I have one, and I have not given up hopes of building a 1970 version of the 350 250 hp combo. That 69 and 70 350/250 combo are the only ones NHRA lists with that venturi size. As someone stated a 1/2" open end wrench will just fit over the dividing wall between the 2 throttle bores. it is a quick way to check if the carb truly is a 1.375 venturi without disassembly to measure. the two small orifices under the baffle held in place by the front booster cluster screws are the hi speed air bleed. they allow more or less air into the fuel well. the drops tubes in the fuel wells can have different size and number of holes. this is the emulsification circuit. the accel pump discharge are the 2 hole on the face of the cluster between the booster they are drill at an angle to shoot into the throttle bores. That is most of my knowledge of the Rochester 2VG other then a lot of builder drill and re tap the main jet holes to take Holley main jets and start in the mid 60's for jets. Ask any question Iwill pass the knowledge if I have it. Last edited by DanBar; 08-16-2025 at 08:07 PM.