283 main clearance problems

1,2,3,and 5 measure .0015 to .002. 4 on the other hand measures .006. I checked the crank and the journals measure the same. Problem with the block? Thinking about moving bearings around and see if the problem follows or stays. I guess the main question is can I run it if it is .006? What would happen?, how low would it bring the oil preasure?


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First step is to check the bearing itself. leave the bearing in the cap and remove the crank then tighten the main cap down and measure the bearing top to bottom, then switch in another set of bearings and measure again. If it`s just as simple as the main bearing then no problem. But if the clearances come up the same the issue is in the main cap and the block will likely have to be line honed. I`ve seen large journal small blocks be ran with one main bearing clearance excessive and it ran a long time, but I certainly don`t recommend it.