Glad you posted back CC, and you too make some fair points. So some good debate.
Remember that the title of this thread is "Lack of Power". From everything I have read it sounds like it is hitting on all 8, just not pulling. If that is correct, and all the vacuum lines have been sorted so there is no major vacuum leak, and the carb is OK, then it ought to go. Here is the lack of gas thread:
http://forums.maxperformanceinc.com/...d.php?t=745946
Key one for me is your reference to "most non-performance Pontiac motors". I admit it has been a very long time since I've owned one of those, and you would not expect that an engine in a GTO would fall into that category, but got to admit that it is possible.
On the other hand we are assuming that he has 061 heads which are big valve, small chamber. And 4bbl manifold and carb. So the only piece that would make it low-performance is the cam. And my assumption has been that it has some sort of performance cam in it. I've run 061 heads with a few performance cams from mild to pretty wild and the best all-in was always around 34-36.
Assuming that it has some sort of good cam (even just a factory 068) it will need timing to develop good power when the throttle is opened fully, and setting the all-in timing back to 24 deg will make it lethargic. If the vacuum can gives it too much advance at part throttle that should be pretty obvious when road testing and then it just needs to be replaced. No problem testing with it disconnected. I would only do that if it showed up as a problem, but for someone not familiar with tuning maybe not a bad idea.
ra96, no doubt this would be a lot easier if one of us could spend a few hours in the garage with Darth to make sure the simple things are right. Unfortunately best we can do is internet advice.