[70oldsW30]

It is hard (or impossible) to troubleshoot over the internet but I can't help but ask how it starts when you first crank it in the morning and then how it behaves when it gives you problems starting it later after having driven it somewhere.

I have rebuilt a lot of rochester and if you mean what kit from the local parts store then I have never noticed one brand to be particularly better than another. I've seen a few of the parts supplied that I liked beter than the other but I've never equated it with the brand of kit. Anyway, I'm no carb expert but that's my experience.