I have a 1972 Pontiac Ventura with a 307 engine. I swapped the stock 2 bbl carb and intake with an Edelbrock 1406 4bbl and airgap manifold (I saved the stock parts, don't worry). The cars manual calls for timing to be set at 8 degrees btdc but it seems to run better closer to 12 degrees or more btdc. Is it to be expected that the swap to a different intake and 4bbl carb would require more advance in the timing? Is there a way to adjust the timing by rpm to find the sweet spot since the factory setting doesn't seem to offer the smoothest idle?