not a 396 just a 323:(

One thing you might investigate is Rhoades hydraulic lifters. They bleed down at low speed so that a large cam has less lift and duration for better idle and low-end torque. There are 2 versions - street and race. I put the original street ones in my 273 (mild 422/444 cam) for better mileage, but haven't run the engine yet. List ~$110, but got mine on ebay cheaper.