Kind of a tuff one for me to answer in a fairly short manner. But here it is in a nutshell. Using that 327 I can only see lower compression pistons and a lot smaller cam to meet your stated goals. The 327 has the right pistons for that cam and smaller combustion chamber heads. Generally if the cranking compression is about 200 or under it is doable. You said you wanted a lot of strong street torque and you won't be tracking it. The problem is the current cam in your 327 Will Not give usable street torque with that cam nor will it like a gear under 4.11 (4.30-4.56 would be better) and a manual trans in that car. This is CLEARLY AGAINST what your stated goals are. Cams that work decent in a torky street friendly 327 are basically going to be RV and large RV grinds. One example is going to be a hydraulic flat tappet CompCams 268 Seat Duration, 218 Duration @.050, 454 Valve Lift, 110 LSA. Even with the cam being that small a 327 will prefer a 3.50-3.70 gear. With a 3.08 gear I'd prefer dropping the cam down a step to something like 260-266 Seat Duration, 210-212 Duration @.050. There are a lot of past 327 builds over at camaros.net that you can look at. Just google the two and you will see plenty.