Just got the 408 in my 69 cuda running. I used a holly street avenger carb. The thing was way rich out of the box. I had to take it to a friend thats a carb man. He spent some time with it and got it right. The reason i'm posting this is in case anyone has this problem. Make sure you oil didn't get any fuel in it, mine did and thined the oil to the point that my oil pressure dropped about 10 psi. I caught the problem with out any damage. So if you install a holly be careful that it is setup right. This carb wouldn't have worked out of the box on any engine combo.