I have a 1985 4bl carb off the old 307. Replacing eng with 1970 350 bored 60 over. Running rv cam, and stock low comp. pistons. Will the rochester off the 307 work ok on the bigger eng? If not can I rejet to size needed? If so what jets do I need?

 

You may want to consider an earlier model carb, that will make your 350 sing. Not saying you can't get the one off your 307 to run, but I think you'd be happier with the early style!

 

When I spoke with Cliff Ruggles he suggested '76/'77 rochester as one of the better choices, has the mixture adjusting screws, 850cfm, and doesn't leak. Consider one of his rebuild kits as well, I'm extremely satified with the HP kit, he also provided me with primary metering, jetting and idle tubes for my cam and compression as well.

 

Im always happier with the older stuff! In the past i have drilled out the plugs and cut slots in adjusting screws,and changed the jets. The carb i have works fine,I just dont want to go to lean! 850cfm sounds like alot,thinking 600 or 650? Wife just got cut to 20 hr's a week so play money is cut!

 

What year is the vehicle and are you running the CCC system? If not, the 307 carb will not work. The primaries are contriolled electrnically by the solenoid, there are no jets. I have a couple of 350 Q-jets if you need one. Most Q-jets are 750 cfm, but the beauty of the design lies in the small primaries/large secondaries, it will only deliver as much fuel as the engine needs.

 

Yes I am running the ccc system, but without the smog pump,cat,and pluming for that. will use ox senser,map, temp, knock ect.