engine cutting out down track after in 3rd gear!

So your saying this engine should be able to idle at 900 in gear without it chugging and wanting to die? I've never ran this big of a cam so I really don't know. It just seems to bog down and want to die at that slower idle. I guess I need to get my butt to tuning it... I stay so freaking busy I never have time to mess with it. And I don't have anyone to help me with it... learning as I go. And it's not doing it at cruise speed at 4k rpm. It only does it a few secs after I floor it. Hard acceleration only.

Yes, if you guet it tuned, it should ldle bow 1000 rpm in gear without chugging down and stalling. Forget about vacuum advance, it has no place on an engine with a big cam. Get the initial advance up in the range of 20 degrees and it will run and idle in gear much better. The throttle responce will be much better also.