Quote Originally Posted by Firechicken
When you change the cam/heads/intake manifold etc. you change the carb tune that is needed by the engine. That's why I was saying before that you need to set the timing with a light and then tune the carb. A vacuum gauge and a tach makes it really easy to tune the carb's idle circuit without guesswork. It will also help you find out if you have a vacuum leak or not.

I would think just based on what you have done to the engine that it is not running to rich; but instead running to lean, especially since you haven't tuned the carb yet...

Dutch
I don't think a 600 Holley on a 283 would run lean un-less some really droped the jet size down.