Camshafts: What effect does increased lift have on performance?

Kern Dog said
Absolutely.
It appears to have been approximately .010 below deck with 5 cc valve reliefs. .020 over, stock 3.58 stroke. I don't know the exact chamber size but online sources show between 63-72 ccs for a '308 head.

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The first and worst case scenario comes in at 10.52 to 1, way too high for an iron head engine on 91 octane. If the pistons were .020 below deck, it gets slightly better:

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If the heads are closer to 65 ccs AND if I used a piston with an 18 cc dish, the C/R gets around where I'd feel comfortable.

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I don't want to always have to run 91 octane with this car...

Your 308 heads probably have 72 cc chambers. Not that I have measured a set, I gave up trying to find a set that wasn't cracked. J head chambers measured 74 to 72 cc if i am remembering correctly. With that hardware on the engine you bought I'd measure the chambers and deck measurement myself before you buy pistons. You can also adjust CR with thinner or thicker head gaskets available today.