Just a couple thoughts! You may have a little too much clearance on the mains but its not all that bad. I dont see anything wrong with 45 to 50 lbs at 2000rpm . Almost seems a little high ar 2000. must be the HV pump. What is your total timing? How about trying it at 32 to 34 total . Your cam selection is good . I do not think the comp 280 is a problem. You never mentioned if you have good headers and exhaust, I hope so, Also what gear ratio are you running ? We're shooting in the dark here a little,so Im just throwing a few things for you to consider. I have built two 406s and loved the performance of both of them, 406 needs to breathe good--good heads ,valves, good exhaust, It doesn't need much gear.Iam just guessing here but I would be looking hard at heads and timing. I hope it turns out to be a simple fix for you. Good luck!