it had a 6.5 power valve on it. i watched a few youtube videos and one said to take the vacuum reading you get when you have the car in drive and divide it in half and if its an even number drop down .5 so for me my reading was 10, so i installed a 4.5. but now i need to start all over since we found the vacuum leak. so i think your right and the number is going to increase, maybe back to an 8.5. im loving my Holley carb and im determined to get it dialed in correctly. thank you very much