318 Motor, please help

UPDATE: Great news!!! Finally had time today to get tuning on my 318 since that vacuum leak was found. the timing and settings were so out of wack that i had a heck of a time even getting the car to start and stay running so i could get started. after a bunch of tweaking on the timing, and starting all over with the air fuel mixtures and adjusting the throttle pumps AND the idle and transition circuits......HOLY COW my motor has never run so good since i got it a year ago. my vacuum at idle now is 22 and when i drop it into gear it smoothly drops to 17 but no sign at all of wanting to stall. i now have instant response when i stab the gas (so much fun!). im sure i have alot more tweaking to do but im thrilled at the difference already. i still have the 4.5 power valve in there, the store near me that sells them isnt open today so im going tomorrow. do you guys still recommend an 8.5 power valve? im also going to buy a tach tomorrow but by ear i CAN say that the idle now sounds MUCH closer to wear it should be. before it was idling way too high, if i had to guess about 1200rpm and i couldnt get it to come down any more. now i would say its idling about 700rpm (should be around 800 i believe) and the motor looks so smooth, not shaking and running like a turd. Damn I'm excited......and P.S. im loving the Holley and would never switch to an Edelbrock.