So I just took off my 600cfm from my 357, car ran like a dream but I felt it could use a bigger carb. Just put on a 750 and can't get it to stay running to save my life. Adjusted both needles, no vac leaks, 6psi at the carb. Stock cam. What's going on?!

 

What is going on?
Is there fuel leaking into the engine? How do the plugs look?
Is the 750 a brand new carb or previously used?

 

possibly stopped up idle circuit. 6psi vac sounds rather on the low side for a stock cam.

 

I'm sure the person is referring to 6 psi of fuel pressure.

 

Yes 6PSI fuel pressure, sorry for not stating that.

The car starts, but immediately dies. If I give it gas it'll stay running but barely. This is a previously used carb unfortunately, but I took the top part of the carb off and checked float levels and anything else of the obvious, found nothing. Took the needles out and blew air in their multiple times, still nothing. It's as if the needles aren't even making a difference.

 

sounds like a rebuild is needed. What was it used on before?

 

Well turns out it wasn't the carb. I bought a brand new one and it was doing the same thing. I had vac leak at the back of my intake. Got another 600 and sold the 750.