Frame rails

[88AMCOMANCHE]

Been working on my truck for about 9 months.FINALLY have gotten around to fixing the "small" rust hole in the drivers floor.Only to find out the entire drivers floor front is destroyed.Have a new front floor pan on order,should have within a week or so. But, My question is: There are a few inner support frame pieces (fat one from side goes almost to the frame,then a Long one runs towards the front by toeboard,becoming thin as it goes) Correct me of im wrong,but dont these "inner frame peices" simply help strenthen the floorpan to avoid twisting or shifting or possibly warping??? OR do they have a different purpose?
Since theyre impossible to find,Im considering just using 3" channel iron since its under the carpet out of site. Opinions? Thoughts?

[4.3LXJ]

Yes, they offer structural integrity.

[xjrev10]

where did you find comanche floor pans??

[88AMCOMANCHE]

where did you find comanche floor pans??

A guy on Ebay has them. As with any Repro floorpan it does require very slight modification. Like hammering down an edge tolay more flat to so it meets the old metal etc. But nuthing too serious. Overall it fits right in & i will end up cutting a few inches off the rear end of the panel,only because id rather cut it off the panel rather than cut from my original floorpan that doesnt need replacing because all my damage is mostly in the Front floor. I typed in "1988 Jeep Floorpan" on ebay.

[LizardRunner]

Those pieces should not be left out. As previously stated by43LXJ they provide structual integrity, without those pieces, your body will flex in ways it shouldn't and that will lead to cracks you never want. Your idea for replacing them with 3" channel is a good one, or you could take the time to form ones by hammer forming, a longer process and not really necessary if your channel is nice thick metal (up to 3/16" thick should provide plenty of beef. Instead of trimming you could add some beef in the area that is still ok by drilling and doing some rosette welds to meld the orig. rear pan with the new one your'e putting in.

[88AMCOMANCHE]

Those pieces should not be left out. As previously stated by43LXJ they provide structual integrity, without those pieces, your body will flex in ways it shouldn't and that will lead to cracks you never want. Your idea for replacing them with 3" channel is a good one, or you could take the time to form ones by hammer forming, a longer process and not really necessary if your channel is nice thick metal (up to 3/16" thick should provide plenty of beef. Instead of trimming you could add some beef in the area that is still ok by drilling and doing some rosette welds to meld the orig. rear pan with the new one your'e putting in.

I need to correct myself here.....I mentioned the inner frame floor support and mentioned using 3" channel iron or something along those lines ......But the frame is actually 4" across up around the seat area & tapers down (almost flattens out) down in the foot area towards the oe board to actually 6" wide. I may have to avoid the "taper" and go wit h the 4" channel iron under the seat & for the floor go with a 6" channel iron & the 2 will be welded together since the inner floorboard supports arent avalable anywhere. But TY , excellent pointers. Will definately take into consideration.

[LizardRunner]

sounds like you have a good plan there. The important thing is to not leave structual items out during the repair.