Identify these holes in the floor?

[thewrai6th]

I don't think these are stock holes, but before I weld them up I thought to ask the board.

Have the cab on the back so I could sand the bottom. Started poking at the front of the passenger rocker and the entire section disintegrated. 6 panels, a lot of fabricating, hammering, welding, grinding and I'm back to where I started.

3 x 1/2' holes by the driver sill. My guess is that this was a line lock, not OEM.

2 small pin holes, would be under the seat near the gas tank. No idea on these.

[402Bowtie]

I think your second picture is for the aux fuel valve that some trucks had from the factory. This is the plate that would mount on the topside of your floor by the driver side rocker panel.

I'm not sure about the other holes in your first picture.

[thewrai6th]

I bet you are right on the fuel switch. All welded up now.
Thanks for the reply!

[MACO]

Mine has the same holes, they don't look stock though. I assumed they were for a fuel valve.

[Stocker]

Yep. My K20 has the stock tank plus two aftermarket saddle tanks, and the valve is the same location as the holes you pictured.

[57taskforce]

Yep fuel valve for sure. The other two small holes probably had screws Thru them with clamps to secure the fuel pluming to the valve.