I'm looking at ordering a full floor pan from OPGI.com for 69 Cutlass Convertible. They come with rocker panels and without. What are rocker panels?

 

The rocker panels are the part below the door. There are inner rockers, which is the part towards the frame rail, and outer rockers, which is the part you see below the door. I suspect that when they say "with rockers" they mean that inner rocker as opposed to simply ending the floor pan stamping before it bends down 90 deg to for that inner rocker.

 

I did the floors in my 69 convertible a couple years ago. Keep your rocker panels if you can. If you don't then you have nothing holding the front and back together. You then have to do something to keep the two ends straight. I kept mine rockers and also the braces across the floor to keep structure. See picture. I ordered my floors from Auto Metal Direct. I was happy with what I got. Good luck.

 

I did a full pan replacement on my 72 convertible. I choose to replace the full floor with braces and INNER rockers, keeping the OUTER rockers intact to preserve the door opening alignment. The floor provides all of the strength so you need to install bracing across the door openings and across the width of the body so it doesn’t bend while you’re doing the replacement.
I leveled the frame on jack stands, removed the body bushings, and installed 12” long 4x4 blocks in place of the bushings so the body was lifted enough to drill out the spot welds but it was still “referenced” to the frame. You will have to drill out a million spot welds so get a couple of special spot weld drill bits.
I bought the floor pan from Auto Direct Metal AMD. the fit was really good.

 

Is it possible to leave the body attached to the frame while cutting out the old pan and welding in the new one? I figured it would be easier to keep everything square that way.

 

Are you using a one-piece floor pan or sections? The one-piece is designed to be welded in from the bottom, but in a convertible you may be able to get it in from the top. Frankly, I'd weld in temporary bracing on a convertible in any case before cutting out the floor.

 

I'm gonna use a full one piece replacement. My rocker panels look good.