454 Rockers not getting oil HELP!

There are a few of the rockers on a 1970 454 BB chevy not getting oil up to them. We have checked the pushrods and they are clear, installed new lifters and rockers and still no oil to a few of them. Always the same ones . The rear most drivers side rocker is getting a great supply of oil but the others on that side are just getting a little and the # 1 cylinder ex rocker is smoked from lack of oil. There are 2 on the pass side that are smoked too. Anyone ever seen this before? Any ideas? Any help would be very appreciated. Engine has about 10,000 miles on it and this seems to have just happened.

Steve