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Technical Model A Sedan body location help!

Discussion in 'Traditional Hot Rods' started by mattyrz05, Sep 2, 2020.

  1. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    Hi all,

    Long time lurker. I have begun a custom scratch build of a 1928-1931 tudor sedan. I have the perimeter frame built, rear axle mounted, engine sitting in it's location I think. I am trying to locate the motor front to back(455 Olds). What has me stumped is that I do not know far back the front of the stock firewall is back from the center of the radiator mounting holes(that is my front reference for now). I see all of the overall pictures of body dimensions in reference to wheel centerlines, but none that I have found have refence to firewall and wheel centerlines. I hope I explained this well enough.

    Thanks,
    Matt
     
  2. badshifter
    Joined: Apr 28, 2006
    Posts: 3,195

    badshifter
    Member

    28/29 have a different firewall than a 30/31.
    You need a body to correctly do what you want to do. Either way, a set back firewall or stretched frame are in your future with that engine.
     
  3. Model A Gomez
    Joined: Aug 26, 2006
    Posts: 1,317

    Model A Gomez
    Member

    I copied Wescotts Model A frame drawing, 28-31 bodies will all fit. All Models have a 103" wheelbase, the axles are straight under the crossmembers. There is a bolt just inside the cowl an all years and it is the first hole in the top of the frame, 31 1/8" from the center of the radiator mounting hole. The firewall is ahead of the mounting hole, the picture is a 30 with a stock firewall, hope this helps. View attachment 4804928 View attachment 4804929

    Photo09091340.jpg C motor 012.JPG A Frame.jpg
     
    Last edited: Sep 2, 2020
    chryslerfan55 likes this.
  4. Never2old
    Joined: Oct 14, 2010
    Posts: 645

    Never2old
    Member
    from so cal

    If it were me I’d locate the radiator and the engine. You’re going to have to cut the firewall no matter what.


    Sent from my iPhone using H.A.M.B.
     
    lothiandon1940 and X38 like this.

  5. rpu28
    Joined: Jan 17, 2006
    Posts: 128

    rpu28
    Member
    from Austin

     
    chryslerfan55 and mattyrz05 like this.
  6. I think the first thing you need to do is set the body on the frame and center the wheelwell at the center of the rear axle. Then you will know where the firewall ends up, and you will know what you have to do to get the motor behind the radiator.
     
  7. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    Hi all,

    Thanks for the replies! Didn't expect so many this quickly! I attached/uploaded pictures of the build. They are current as of last night.

    This is a custom designed frame that was built on top of the old Total Performance Model A frame jigs(friends with one of their former welders). I know that the front and rear cross members are located correctly and that the rear is located correctly from the front mount as shown in Gomez's dimensional picture. I just was wondering if anyone could tell me the tape measure reading from the front of the stock firewall position to the hole used to mount the radiator. I don't have access to the old jig or paperwork from TP.

    I would go by what most are saying about mounting the body first, I just don't own one of those yet. I am trying to build as much as I can before I have a body. I only have a 1 car garage and am trying to be efficient with space. I am also doing it this way because of parts availability(I already had the frame and all of the other stuff has been given to me by friends).

    Thanks! Matt
     

    Attached Files:

    Last edited: Sep 2, 2020
  8. general gow
    Joined: Feb 5, 2003
    Posts: 6,263

    general gow
    MODERATOR
    Staff Member

    could you maybe borrow a cowl from someone to mock it up?
     
    Tman and brEad like this.
  9. sorry, I thought you had the body. do you know anyone that has a model A? They all have the same distance from the firewall to the center of the rear axle. Measure one and lay it out. I really think you will need to start with the rear axle center line as it sounds like that is the one thing that has been decided on at this stage. No matter where the firewall is the body will have to line up with the rear axle.
     
    panhead_pete and lothiandon1940 like this.
  10. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    I wish I did. I am "new" to hot rod building. I have done bracket designing and fab for a lot of others, just never a whole car. I don't know too many people around my area that has any Model A's.
     
    chryslerfan55 likes this.
  11. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    No worries! Sadly I don't. I have located the rear axle by measuring from where the front axle would traditionally be. There are lots of basic dimensioned photos on the MAFCA website. I used those to get the rear axle dimension from the front cross member. I just can't find anything on the good ole internet that has front axle to front of firewall. I see lots of drawings that dimension to the front body bolt location, it's just missing a little info that I'm looking for. The hunt continues.
     
  12. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    This is more or less how I'm going so far. I think it'll end up being how I get from where I am today up to the point of dropping the body on.
     
    chryslerfan55 likes this.
  13. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    All,

    My main point of questioning myself comes from having a chassis that isn't conventional(6-1/2" kick in the front and 13" kick in the rear) compounded by a rather hefty motor. I'm just trying to get an idea as far as where the front edge of the cowl is in relation to the back end of the motor. It is currently set up with a tall-ish HEI distributor and seems like a tall motor. I just don't want the top of the valve covers/distributor to be sticking up through the cowl. The body is also going to be channeled by 3" and then chopped 5-1/2" to 6".
     
    46international likes this.
  14. You need a body or at the very least a cowl like @general gow said to mock it up and do it right
     
  15. S10_Man
    Joined: Oct 29, 2018
    Posts: 18

    S10_Man

    There's good advice about the cowl on here. You have to have something to start with, no amount of measuring will replace the real McCoy. Just as a suggestion, I would ditch that TH400 for a Th350. It's a tough trans, but is heavy and soaks up nearly 40 hp just to run it. Your car will be a featherweight compared to an Olds 98, and properly built, the TH350 will take the power. Overdrive? Well, you can't escape size and weight, but with a 455 I'd avoid a 200r4. Good luck on your build, sounds like you have the patience and persistence.
     
    46international likes this.
  16. scrap metal 48
    Joined: Sep 6, 2009
    Posts: 6,044

    scrap metal 48
    Member

  17. panhead_pete
    Joined: Feb 22, 2006
    Posts: 2,531

    panhead_pete
    ALLIANCE MEMBER

    You didnt extend the wheel base at all when you built the frame? Just looking at your pics the Z in the front of the chassis seems well forward of where the cowl will land based on where the engine sits? On this frame here the Z is at the cowl so hidden.

    31acoupe 015.JPG
     
    Last edited: Sep 2, 2020
  18. I just went down and measured mine, from the center of the rear spring to the front outside lower edge of the firewall it is 75". now my body was VERY rusty when I got it and it had no subframe or door sills, so all that is now home made so a stock body may be a little different. Which brings us to another point, it may be time to start shopping for a body. I know budgets, time and space may get in the way but you don't want to build some nice motor mounts, radiator mounts cut driveshaft and all just to find out you need to move everything 1/2" one way of the other. other than that the 75" should be close.
     
    Last edited: Sep 3, 2020
  19. Not to mention the size, space goes away very fast in a Model A
     
  20. My '30 Tudor is chopped 4" channeled 2 1/2" just enough to cover the frame. I still have a rear seat but the front seats are pushed back a little.
     
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  21. manyolcars
    Joined: Mar 30, 2001
    Posts: 8,354

    manyolcars

    What is a perimeter frame and how is it different from the original frame?
     
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  22. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    Hi, It's a racing term that I used. It basically means that I have the two main rails, front cross member and rear cross member, nothing in the center yet. Different due to it being constructed from rectangular tubing vs c-channel.
     
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  23. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

  24. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    Thanks for the info on your build about moving seats back. I don't think I'll be using the rear seats at all. Not solely based on the rear kick in the frame, just not sure that rear seats is something I want to have in the car. I have some other ideas for that space, especially with no kids.
     
    46international likes this.
  25. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    Thank you so much! This will get me going. I guess I'll need to find a body before I had anticipated on needing one. Small garage problems.
     
  26. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    chryslerfan55 likes this.
  27. sloppy jalopies
    Joined: Jun 29, 2015
    Posts: 4,122

    sloppy jalopies
    ALLIANCE MEMBER

    are you running a hood ?
    if so it will tell you where the firewall will be located,,,
    .
    IMO... I would borrow the same year cowl as your body to get the front 3 holes in the right spot...
    and reverse the '30-'31 firewall if using that year body... best of luck !
     
    Atwater Mike and mattyrz05 like this.
  28. mattyrz05
    Joined: Nov 20, 2012
    Posts: 17

    mattyrz05
    Member

    My plan is to use a 30-31 grill shell and hood. No side panels though.
     
    chryslerfan55 likes this.

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