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TECH: Flipping a Model A Firewall

Discussion in 'The Hokey Ass Message Board' started by Crusty Nut, Mar 5, 2008.

  1. Crusty Nut
    Joined: Aug 3, 2005
    Posts: 1,834

    Crusty Nut

    When I decided to do this I looked for some insight. Lots of people said how easy it was, but there really wasn't a how to. It really was easy. Mostly, this will just give some better photos for those of you considering doing this. The way a 30-31 firewall comes foward, I think this is a better looking solution than cutting a big hole and filling it with something like a wheelbarrow. It really didn't cut into the foot room very much.

    First off, here is what you are starting with:
    Take some measurements of the opening for the gas tank and drill out all the spotwelds and rivets. Some of them are hard to find.

    With it removed:

    Hold it in there and eyeball how much needs to come off the toeboards:

    Cut away. Note how the "foot" of the firewall is separate. It will come off and get turned around also.:

    More in a minute.
  2. Crusty Nut
    Joined: Aug 3, 2005
    Posts: 1,834

    Crusty Nut

    This part will need a little hammer and dolly work and a couple relief cuts:

    Fitting pretty good down low:

    Take some mesurements up top:

    Cut up a really nice gas tank, since only the skin will fit now:

    More to come
  3. Crusty Nut
    Joined: Aug 3, 2005
    Posts: 1,834

    Crusty Nut

    Starting to fit pretty good:

    Once it fits, use the holes you drilled and spotweld it in:

    Here is a better shot of the foot. It needs a small filler piece still.:

    Thats it for now, just some finish work. The way the toeboards go back together really minimizes the foot room loss.

  4. chaddilac
    Joined: Mar 21, 2006
    Posts: 13,867


    Wow that's pretty cool, I've never see one done before!

  5. GTSDave
    Joined: Jan 10, 2008
    Posts: 133


    Thanks for the pics! Looks great.

  6. duke182
    Joined: Nov 27, 2005
    Posts: 562


  7. flathead31coupe
    Joined: Mar 23, 2006
    Posts: 1,596

    from indpls, in

  8. Mullda
    Joined: Apr 12, 2006
    Posts: 303


    Nice post! I heard it talked about and seen the results, but never saw how it was done. Really nice. I wish I'd gone that route with my '30 instead of putting in a recess.
  9. BJR
    Joined: Mar 11, 2005
    Posts: 6,803


    Do you have to do anything about the bellhousing bump out being the wrong way (toward the front) now? What about the very bottom angling forward instead of backward?
  10. gashog
    Joined: Dec 9, 2005
    Posts: 978


    Great post, thanks! I never thought about the fact that you would no longer be able to use the stock tank.
  11. garagerods
    Joined: Dec 15, 2006
    Posts: 451

    from Omaha

    Nice and clean!

    We did one some time ago and cut out the lower portion and turned it back around.

  12. bigdreamsnobux
    Joined: Oct 6, 2005
    Posts: 222


    This is perfect for my A project right now, great pics since I had seen a finished version but never the 'how to'. Keeps the firewall looking stock rather than a wagon inserted and looking like a fiberglass mould. Very nice.

  13. Crusty Nut
    Joined: Aug 3, 2005
    Posts: 1,834

    Crusty Nut

    Me too, thats why I wanted to put this up.

    I depends. Not for my motor of choice. The very bottom flange can be cut off, then attach the toe board to the next up bend. When it gets flipped it kind of makes a new flange in the right direction, just up a half inch. Did that make any sense?
  14. HHRdave
    Joined: Jul 31, 2006
    Posts: 1,068

    from So Cal

    Nice work, great pictures... my only suggestion: I would like to see all the metal cleaned before welding. Welding onto rusty metal is not a good idea.
  15. moses
    Joined: Dec 7, 2004
    Posts: 1,101


    looking good...jeffrey
    Joined: Aug 28, 2005
    Posts: 1,866


    Thanks, I want to do that do mine. Now I know how.
  17. Reverse firewall
    Reversed firewall
    Reversing firewall
    Awesome tech thread, just adding Terms for searching so the next Guy searching can find it .
    -Brent- and zapp69 like this.
  18. striper
    Joined: Mar 22, 2005
    Posts: 4,498


    I can appreciate why you would do this and it is probably the most "factory" looking way to make space but I think it's a real shame. The '30-'31 firewall is my favourite of all the early Fords. That bulbous look is unique to this model and looks really nice on an open hooded car. Good work on the conversion just the same.

  19. The37Kid
    Joined: Apr 30, 2004
    Posts: 27,884


    Nice job! Thanks for posting the info. If you don't know it already you have an early 1930 with the multi clip cowl band, later ones don't have the square holes in the side panels.
  20. mullskull
    Joined: Dec 30, 2009
    Posts: 217


    i'm in the middle of reversing the firewall on my 31 pick up... i was wondering how you tackled bottom of the firewall, around the foot.... did you shorten the fire wall, or modify the hell out a the front mount area, specifically the part of the sub-rail that sandwiches the firewall between the cowl?
    it looks like you may have done both??
    i'll also be channeling the cab, but i wanna fit the firewall first-
    any feed back would greatly appreciated!
  21. porkchop4464
    Joined: Jan 20, 2009
    Posts: 879


    Awesome! I love this freakin site, man! You guys are just flat out gentlemen and awesome. My mind is made up; I am gonna do it! But I want my firewall completely flush, so I am thinking of filling 1 and 1/2 inches of the recess with plywood after welding and bolting teh firewall back up reversed, then skinning the wood with a piece of polished alum (a huge road sign a friend gave me). In other words, once recessed (flipped) I will stencil 3/4 plywood, screw it from the sides in place and then interior grommet washers with screws around the outer edge. I want a flush firewall with no curves and a polished finish. I also still think I am going to leave the bottom alone and let it stick out a few inches. So many of the 32s leave them that way, and I think they really look cool. It fills the engine bay a little better as well.
    Thanx again a million times, guys! I will post some pics this weekend after work when I am cutting, flipping, welding. and tinkering. It is hell time I get a move on on this pig.

  22. LeftCoastErik
    Joined: Apr 23, 2010
    Posts: 907


    Good stuff..I hate the aftermarket panel I got, but I got a nice stock firewall also. I think I will go that way!
  23. Great info please mod's put this in the tech section.
  24. 48fordnut
    Joined: Nov 4, 2005
    Posts: 3,939


    Came in to ask a question about this, did a search and came up with all the info I need.Thanks, to all.
  25. Any pics of the finished car?
  26. nexxussian
    Joined: Mar 14, 2007
    Posts: 3,240


    It appears to be his current avatar. :)

    Other than that, I dunno.
  27. nxcess
    Joined: Mar 30, 2013
    Posts: 109

    from Mesa, AZ

    There was an article in I believe Street Rodder mag a couple of months ago showing this.
    Good job.
  28. brady1929
    Joined: Sep 30, 2006
    Posts: 8,550


  29. captainjunk#2
    Joined: Mar 13, 2008
    Posts: 4,393


    you made that look easy and I think the firewall looks way better reversed great job

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