Looking for advice on a camshaft upgrade for the zz502/502 crate motor. Motor is well broken in, runs very strong, but is way under-cammed. Would rather not change valve springs, pushrod length, studs,etc. unless it is really going to be worth the trouble. Was also thinking different intake (RPM air gap?) and carb (speed demon 850 dp?) may match up better with a cam change? Hard to get any kind of advice from GM that seems reliable. Chevelle is in the high 11's, looking to get into the low 11's. Thanks.