rear frame rails


Veteran Member
Dec 18, 2022
as you know i'm replacing all floor pans in my 75 LT or RS ill have to look at my cowl tag i forgot. anyway tne rear frame rails were not welded to the floor pans. welded the driver side rear seat pan in and plug welded it to the frame rail. question is seems to be a gap in the front of the frame rail spring pocket location. noticed no spot weld remains in that location. driver side i beat and adjusted the floor pan in such a way i was able to spot weld in a couple locations. cut out the passenger underseat pan out and noticed a gap in the frame rail as i spoke of. i dont think i should massage the pan as i did the driver side. can one of you fine members let me know if there is a factory gap? i'm thinking yes cause it looks that i cant stretch the pan that far i dont think i screwed up by welding the drivers side up i anything i added strength . i'm thinking of just letting the gap stand and rust proof ..the crap out of the inner frame rail. and plug weld or as some say rossett weld where existing factory welds were the gap shows no evidence of factory spot welds. i am using 3 picece floor pans each side with the driver side completed.


Veteran Member
Nov 13, 2020
I replaced my torque boxes and rear floor pans in my car and I recall a gap between the rail and pan on mine, too. Passenger side rear floor pans required a LOT of massaging to get them in right.


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