What do I look for (and where) to verify that an engine is a "power pack" 327?
I know that there will be a specific marking on the heads, but am unsure of anything beyond that. Thanks for the help!

I'm not completely sure, but I think you look at the block near the distributor, back by the where the engine bolts up to the Bell housing. There is a series of numbers there that you may be able to reference in combonation with the numbers on your heads.