Carb issue?

Hysteric said
Why do you gave an unstable idle? I ran a bigger cam with an 800 avs in similar cubes and still managed to get 9 inches. If your idle is fluctuating you need to find out why.

Have you checked your plugs?
have you check your leads?
Have you done a leak down test to make sure all your valves are sealing.

You can try another carb but I don't think that is the real issue here.

I am not sure what your elevation is but you lose an average of 1" of vacuum per 1000 ft of elevation. The manufacturer rates the cam at 10-12" of vacuum at sea level. Also as previously mentioned if i allow a small amount of air it via a small vacuum leak or barely holding open the secondaries my rpms and vacuum raises to 10-12" and becomes steady.

An 800 cfm has larger butterflies that allows more air to get by and may work. As mentioned in previous post the 650cfm may be a little too small for the build, but i had a new one on the shelf already.

- Compression test was 160-165 cold and dry on all 8 cylinders.
- plugs are becoming black from being way too rich
- machine shop went through the new heads and performed a leakdown test on the bench, but possibly perform one with everything installed.