Conflicting carb advice in 1969-70 Technical Forum Posted July 3, 2017 · Report reply 2 hours ago, Rsanter said: Yes, that is the kit you need if you are going to be messing with those carbs. While i I do agree with what was said about the 600cfm not being too big. There are advantages and disadvantages to what size carb you use depending on your usage. the carb size is based on what the max RPM you will be using will be. If you have a 302 and will be road racing then you will need a bigger carb than a 302 cruzer if you have big ports (like a boss 302) and a single plane intake and big headers as well as the cam that can handle it, then you can use the bigger carb. If you have stock 302 then while you can make it run with the 750cfm carb. You will not get as good of throddle response or metering accuracy from that setup. the 600cfm will work fine if properly setup. If you are getting gas smell at idle then I might suspect that you are not just on the idle circuit but perhaps the setscrew for the throddle blades needs to be backed off. it is also possible that you have a float not setup right and you might be pushing too much fuel into the carb and have a little bit of overflow dumping int the engine. if you are rich on running then you need a bigger needle or smaller seat, or both. Actually this what is often called the metering rods and seat. I think I would try to get that 600 set up correctly before I tried someone's used 500 bob 8 Hey Bob, This car is a total cruiser. I already have the 500 and I think that I'll work with that one both are going to require me buying a calibration kit and rebuild kit so I'd rather use the one that is right than the one I should be able to make work.