I was at the Pontiac Nationals last year and asked a rep at both Performance Years and Ames if anyone repops floor pans for the tri five Pontiacs. "Nope", from both, but the Ames rep was nice enough to tell me that most people rework tri-five Chevy floorpans and weld them in. He claims that dimensionally they are the same and can be put in the Ponchos but the ribs are different and some tweaking will be needed for the different frame width and some of the crossmembers are different. He wasn't sure exactly what was needed to do this. I did a search and couldn't come up with much. I ordered the 1/2 pans for the tri five Chevys today and will be putting them in my 55 Cheiftain so before I re-invent the wheel I was wondering... A. Anyone already do this? B. What were the big obstacles? C. Any pointers? D. Is anyone interested in me taking pics and putting together a "How To", or "How I did it Thread"? The toe boards and trunk pans are entirely different. It appears SOME of the crossmembers are identical?!?!
I had to modify the 55 pontiac rear seat I got to fit the 55 chevy floor. The hump is not nearly as tall in the pontiac. But hey, if you have a wire feed, plasma, and some extra metal you should be able to make it work.
Squirrel good to know! I got the backseat out a 57 Ponch 4 door. The 4 doors have a bigger corner radius to ease in and out and it just so happens this will also give me the clearance for the rollbar. Went to the local latemodel boneyard and to my suprise they had a '57 Poncho there....pulled the seat and paid the $20 the guy wanted for it. @ Scrap metal 48, Stock master cylinder is long gone. I'll be using a Wilwood underdash swing system or possibly reinforcing the firewall and mount through the firewall using a dual reservoir system.
Curly, I realize that this is a very old post, but what happened with your 55 Pontiac flor pans? I have a very solid 55 chieftain that just needs the left front floor. I suppose I'll have to just get a Chevy pan for the repair, but thought I'd ask how yours turned out first. Thanks, Mike
Back in the day I put a complete used '55 Pontiac conv top assy, rear seat and trim in our '56 Chev that suffered a interior fire. As I remember it all fit without a problem.
For anyone interested they are regularly available on eBay for 55-57 Pontiac. May end up eventually ordering a set for my 56.
I rarely come on here so I was shocked to see this old post. The Chevy pans worked out great. I had hardly anything left except the rear seat area. and I grafted the two together so I could keep the stock rear seat. The Chevy's driveshaft tunnel is higher than the Pontiacs from firewall to under the rear seat. The floor braces do not contact the pan in the are of the tunnel. If I would have had more of the original floor I would have gone with the e-bay pans for the Pontiacs. My was so wasted when we lifted the body off of the frame we were wondering if it was going to wad up. The rockers were almost non existent and the floor was long gone.
Not that those won't work but they appear to simply be a piece of sheet metal cut to fit with a couple ribs pressed into them unless that is just a generic pic.
First thing that popped up on Ebay. I just finished making my own. Cost me $80 in 18ga sheet metal. Tools used were a cheap HF 30" brake, HF bead roller, grinder and MIG welder. About 1/3 of the way down...…. https://www.jalopyjournal.com/forum/threads/evinthos-54-customline-build.1184398/
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