The more I thought about my previous post the more I questioned it and then Techinspector confirmed my doubt – the heads and cam are just not going to work well together.

It appears that you have already procured some 882 heads. While I hate to “spend twice”, I would encourage you to put your 882 heads and intake manifold on Craigslist or E-bay and procure some Vortec heads. The Vortecs have a 62-64cc chamber which will increase your compression 1 full point over the anemic 76cc of the 882's. Have a machine shop relieve the heads to accommodate the increased lift (stock Vortec is good for .420). That will make a huge difference and respond well with the cam you’ve selected, a Performer RPM manifold, and any of the vacuum carbs described above.