Block tubing, got some questions.

I would never even consider using a one piece (20-22 inch) and pounding it in. Two 10 inch pieces work well. May sure you truly understand the oiling system and double check to make sure you redrill all oiling holes and make sure the lifter clearance is set properly. Use oil on the preening tool and I ended up welding an extension on my peening tool to get me above the deck surface so I could put vice grips on my tool so I could slowly drive it in some and screw and pull it out. Then drive it in again.