Just rebuilt 66 289 with very mild cam, performer intake, and holley 570 carb. The problem is when I'm cruising at a steady speed car seems to hesitate or stuble. The best way I can discribe it is if you were moving the gas pedal ever so slightly, changing the load but I'm not moving my foot. Hope this make sense.

 

That's called surge and the primary cause is poor carb tuning. The good news is that a primary jet change can usually fix it. Try two steps richer, but frankly, you should go through a whole tuning process on the carb. It is not hard and you will learn a ton.

 

DO you think its to rich or to lean.

 

Surging is usually caused by the engine running lean. Of course, I am assuming surging based on your description. Try going two steps richer and if the problem gets worse, go four steps leaner. Also, did you adjust your idle mixture? It controls mixture on a Holley up through about 1500 rpm. Adjust each primary adjustment an equal amount to achieve the highest vacuum. Start by turning each screw in cw until they seat and then back out ccw 1 1/2 turns. That gets you close and then tune from there.

 

My guess its a Holley carb?

 

Yuppers.

 

Whats that mean?

 

If it is rich enough to bog, your plugs should show a very rich condition. If your plugs look good, then it is probably a lean bog. In a rich bog, the car will feel like it is drowning. In a lean bog, it will noise over from lack of fuel. A lean bog may also feel like a miss if it is a short duration bog.

 

My brain is not working. Duh.......A common problem with Holleys. It seems that Edelbrock really shines in that arena.