Help getting started on complete floor replacement on M170

[CDBurck]

What did I get myself into. Finally removed tub from frame of my M170. It is more rust than metal. sides ok but floors toast front to back. I can find after market rear floor and even found it mentioned on this forum. The question I need an answer for, which was not answered in the other post, is can I use the complete front floor pan for a M38A1 to replace entire front pan of my M170? If it is not a direct replacement is that the best starting point? If I were to post a picture of the tub with back lighting you would mistake it for a picture of the Milky Way. Any suggestions for best replacement approach will be helpful.

[Investig8]

For what it's worth, I took my M-38 to a local metal fabricator and had the really bad places replaced. He didn't have to do the rounded portions around the transmission area so it wasn't that difficult for him. I must tell you it was a little pricey. I have included a photo for your viewing pleasure.
Dennis

[wesk]

I noticed only tack and spot welds on the tub bottom. Did your shop finish bead welding on the top side or did he leave you with only Tack & Spot welds?

[Investig8]

This photo was taken prior to the finished product, although he added many other spot welds, the entire joint was not bead welded. I followed his work with seam sealer on those joints and finished with a rubberized undercoating. Photo below.
Dennis

[wesk]

Hopefully your sealer will keep the remaining rough bare edges from corroding. Did you apply the sealer before or after the painting?

[Investig8]

Wes,
I applied the seam sealer prior to the undercoating and yes, I hope the joints won't rust over time...

[CDBurck]

There in lies the problem, the whole floor is the really bad place. Who ever had this before me had slapped some sheet metal patches over the floor boards so they were not doing the flintstone imitation. The patches have now rotted through and even thing is pretty much gone. The rounded portions around transmission tunnel are about half there but metal that remains is tin foil thick. That is why I think my best bet is complete new floor pan. Not afraid to weld it in, although will need a little practice it has been awhile since I did much welding. But there does not seem to be a lot of support for M170 components so I was hoping someone might know a good way to start. I have thought about starting with:
1. M38A1 front pan
2. CJ6 front pan
3. possible CJ6 complete tub
Just do not have the knowledge base to determine which path would require the least adjustments to get correct fit.