bored blocks are just starting down the road of no return unless you sleeve all 8. Nothing wrong with a 10-20 under 340. The sleeve is rough bored to under 4.04 anyway so youll have to bore that to meet the others and if its a stock block there may already be taper on the old cylinders. Look into a 360 block. Cheaper, More 4.00 pistons available but you'll lose a few cubes but no matter and you can get a roller option. Ohio crank makes a 4.25 stroke crank for a ~426 inch LA stroker.
