Is anyone familiar with a 9381 Holey carb,  I have a modded out 471 olds that likes gas!!!, the stock holley carb has 78 jets all four corners with 6.5 power valves installed on both ends.  any advice on jet size or power valves?  I think I need to block off the secondary power valve with a 84/94 jetting for more power, anyone got any ideas?  Also where is a performance shop, or the best place to buy a holley jet kit in Las Vegas?