89 K5 floor pan repair?

[Zelph]

Hi guys, back with a few more questions. As I understand i should stop drill the ends of the cracks then weld up the cracks? Would a 10 gauge sheet welded over the area be thick enough to prevent more cracking? These cracks are on the rear outer bucket seat mount.

also there is this rubber? Type stuff applied to the front floorboard area. It appears to be factory install? I assume to stop vibration noise? Can I remove this and put down kilmat or something comparable? or Just leave it be?
thanks.

 

[MarineOne]

It's a rubber type thing yes. As for Cracks I would yes drill ends so to prevent cracks I'd then weld them up and grind flat then for extra safety a plate welded overtop for added strength I drill holes in my cover plates to plug weld and then grind flat if u want too