Mine bogs out like that too, unless it's been running for quite some time. EVERYTHING fuel related on it has been replaced with brand new, so I'm assuming that's just the way these old engines are. Kinda [censored] me off though when a Dodge truck close to the same age as mine (it was a 66, mine's a 61) started up beside me, revved quick (nice Vroom Vroom, not sputter, then vroom like mine) and took off rather fast. He had a 225 slant six in it, I chatted with him for a while. Were these Chevy 235s with the rochester really that finnicky? It runs good but I feel that it could still run better.