74 chevy 3/4 ton floorpan ques?

[BirdDoggin]

Hello to all as I am new this is my first post!

I bought a 74 3/4 ton Sat. for $800 that is in need of sum new floor pans. I have never replaced floorpans before and had a few ques? I have found sum from classic industries and was wondering if anybody had any feedback on them as far as how well they fit? Should I completely remove to old ones, or just until I reach good steel again? Any tips and info would be greatly appreciated.

[Chris Guthro]

Id wait until you got the panels in your hand so you dont cut to much, im goin to be doing this stage very soon, but just regular flat steel with diamond plate over top of it

[BirdDoggin]

Yeah I have been back and forth between buying and building. I think once I get the carpet out I will have a better idea. Diamond plate is a good idea.

[SeanPaintsFlames]

Diamond plate can actually be a bad idea. The aluminum and steel together can cause even faster rusting than the rusty stuff you have now. Just order new pans, and when you get them, trace around them with a sharpie, then cut an inch or so inward of that line, removing the old rusty floor section. Drill Sharpie-sized holes every 6" or so around that same 1 inches of edge on the new pans, clamp/hammer/screw the new floors to the old floor, and fill the holes with weld, welding the new to the old. Make sure you ground the welder to the old floor as well. It's pretty straight forward once you get into it.
Don't forget to use etching or epoxy primer and seam sealer to finish it all up. Leave no way for water to get into that old-to-new seam.

[79beater]

I just about finished today putting floor pans in my 79 GMC. I bought mine from lmc and they did not fit very well. I had to do alot of reshaping on the new panels. I drilled all the spot welds and cut the new panels to fit perfect with all butt welds except where the spot welds were. I drilled holes in one panel and filled with weld to replace the spot welds. Lots of work but makes it look almost factory.

[donut]

When I did mine, I only took the bad metal out.

I was able to cut the floorpans to fit, but ended up repairing the supports, cab mounts, and kick panels as they were all bad also.

[80stepsideguy]

Besides floorpans check the rest of your cab like floor pan supports, inner rockers, inner cab corners and replace what is rotted.

thanks
Pat