Junky is right. 58's are different and you want to be sure your mounts/supports underneath actually reach the frame as they should.Anything can be made to fit, but the true answer is no.. Get the correct floor pans and make your life a lot easier.
You live in Virginia and you are having problems tracking down a junk 58' to pull the floors from? I'd image there must be tons of 4dr sedans laying around with good floors. If I were you I would contact your local chevy clubs and ask them if anyone has any 58' stuff laying around. Car club guys know where the cars and parts are.Junky & 64 Superstock, okay, I thought I would try to think a little outside the box. My car needs full floors and the patch panels aren't enough.
Finding full floors for a 58 has been a little tough...the joys of restoring a 1-year Impala.
Thank you & Happy New Year everyone, Juan.
The chrome work on the Buick and olds is a killer, humongous expense, but a beauty when done.Be hard not to fix one of those Buick's or Pontiac's.