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1948 Plymouth coupe looking for chassis ideas.

Discussion in 'The Hokey Ass Message Board' started by youreviltwin, Jun 9, 2010.

  1. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    Hi all I'm new to the forum but not to the sport and i was hoping some of the seasoned members with more experience can chime in and share their thoughts or any information in regards to what i am trying to do.

    I recently inherited a 1948 plymouth coupe from my father who passed away last Dec. I sold all my projects and decided to build this one since it was a dream of his for the last years he owned it.

    Wtih this plymouth i was wanting to put s10 suspension in the front and a gm diff i already have for the rear. The thing is i have alot of s10 aftermarket parts and thought i could save some money using what i already have.


    my goal is to build a nice rod that looks like i just got it out of a barn threw some air ride on it along with some wheels from the outside but along with this look i do want a well balanced performance machine. I want something i can drive accross country if i wanted to, take to the drag strip for fun, autocross it, and just drive the shit out of it.


    im building a chevy small block for it that will spray 200 and want to bolt it to a t56 trans. the rear end that i have is a grand national rear end which would be just fine for now.


    what i need help with is the following.


    I do not know if i should retrofit all the s10 suspension components onto the stock frame and then add additional bracing and c notch for clearance of the diff to be able to slam it on the air suspension or if i should opt for a full s10 chassis swap and make the brakets and braces needed to hold the body and panels on it.

    i was wondering if anyone has done this before on a car like this or similar and any thing i might encounter along the way if i do decide to do this.

    i wouldnt want to go one a bigger missions swapping to an s10 frame if i could just add on what id like to the stock frame.

    it doesnt have to be front s10 suspension but i would like something that is wishbone design and can fit 5x4.75 wheels and brake combos.


    any info that would help shed light on this post will be greatly appreciated.


    thanks

    twin
     
    Last edited: Jun 9, 2010
  2. BuiltFerComfort
    Joined: Jan 24, 2007
    Posts: 1,620

    BuiltFerComfort
    Member

    First, get yourself over to the P-15/D-24 forum, and ask them. Pictures would help too.

    The Grand National GM rear is probably too wide, I think you need something about 60 inches between the wheel mounting surfaces.

    I don't know how easy it would be to stub-frame the S-10; I know that mid-year Dakota pickups (the first ones with 5-bolt wheels) are a good fit with the Plymouth frame. You will need to mark the current front wheel location, pull everything off the Plymouth front (suggest jacking it up exactly at ride height) and trial fit the S-10 stuff in. Lots of front end stub frame swaps are detailed here on the HAMB, the important part is to measure many times (up/down, left/right, square) before doing any final welding, and make sure it is STRONG.

    These cars already have a IFS and you can adapt a Caviler rack and pinion to get power steering. S-10 Blazer rear end may work, or Ford 8.8 from an Explorer is the right size too. If you go with a S-10 front end and GM rear you will have Chevy pattern wheels all around; if you use a Dakota front end and Ford 8.8 rear you can use the stock wheels or go with most any Ford/Mopar wheels.
     
  3. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    thansk tom. so what you are saying a dakota frame would be a better swap and then i can swap the gm suspension and lug pattern stuff over to it?

    where would i find that forum you spoke of do you have a link you can share with me?

    ive put an s10 frame on a 48 chevy pick up and it took some modifying of course but i feel it was a huge mission as to where my buddies told me a mustang 2 front end would've worked in the front and been an easier set up.

    the thing is i do not want to go with something i think would be better and it end up being more costly and more fabrication than an alternative that wouldve yielded saving money and time.

    thanks again

    anyone else have any ideas?
     
  4. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    oh and since i forgot to add it in the first post my car is a 1948 plymouth coupe p15
     

  5. 6berry
    Joined: Apr 12, 2009
    Posts: 352

    6berry
    Member

    i swapped my 48 plymouth sedan on to a long bed s10 chassis. the chassis was already setup for air bags and i got a really good deal on it. it would work the same for you car because all 46-48 plymouths have the same wheel base. the frame is a little bit skinny for the plymouth but im gonna fill up the extra area with some fat tires.
     
  6. Billa212
    Joined: Mar 23, 2008
    Posts: 159

    Billa212
    Member
    from Milwaukee

    Those bitches are narrow...I got a chrysler 5th avenue rear and ifs for mine
     
  7. BuiltFerComfort
    Joined: Jan 24, 2007
    Posts: 1,620

    BuiltFerComfort
    Member

  8. PatrickG
    Joined: Jun 19, 2007
    Posts: 167

    PatrickG
    Member


    everyone wants to run out and do an s-10 swap on everyhting. but the suspension on the p15 really doesnt need that much. do a front shock relocation (search this on the p15-d24 forum), a disc brake swap (rustyhope.com) and a rack and pinion if you are really serious and youve got a pretty modern suspension for much less work and money than a whole frame or front clip swap.

    A pair of bags would slip into the stock front coil spring location pretty easily. and it wouldn't be any more work to c-notch the stock frame than an s-10.
     

  9. I'm with you on this. Everyone is so quick to do a chassis swap. I have over 30,000 miles on mine since I got it and went through and rebuilt the stock chassis. The shock relocation is super important.The stock brakes are pretty damn good. The fronts have 2 wheel cylinders per wheel. Mine stops better than any of my buddies cars, even those with the mustang II front ends with discs.

    The only thing I really want to do is change the rear axle. A Jeep Cherokee 8.25 is perfect width, bolt pattern and is pretty damn stout and super reliable.

    Good luck! Keep us posted.




    BloodyKnuckles
     
  10. Like others have said, nothing wrong w/the stock suspension if it's all tight.
    My brother drove his stock 39 Dodge to & from work for a couple of years and logged 5-700 miles a week on it w/out any problems.
    Personally I would at least upgrade to disc & swap in a later model rear end for better highway gears, 60's Mid-Size Mopar rear ends is a bolt in, but you will have to rework the driveshaft.
     
  11. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    great. thats what i was hoping to hear. i know s10 swaps are popular but i have done one my own and have noticed the saem type of fraem work can be accomplished easier without having to do a frame swap. i really do aprraciatte everyones input and i wil look into all of this info you guys ahve provided me with.

    id like some decent sized and performing frond disck brakes since i plan on putting this thing to work when its done. i knoq it may be a long shot but im looking to brring some kid of competition to my buddies with their new 5.0 mustangs and 335i bmw's.

    everyone in the car game that i know is all about the ricers and the newest baddest cars so realiitically i know it will require to much work to be able to hang with them im trying to get it as close as possible. i do plan on doing all kinds of motorsports im allowed to do with this so i need to bring it up to date.


    thanks again.
     
  12. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    now another question is if i was to do this stock chassis mods for the front suspension would it be able to have room and clearance for a shockwave air ride mcpherson strut shock/bag that they offer. im looking more for those since theya re adjustable over the bag and shock set up.
     
  13. BuiltFerComfort
    Joined: Jan 24, 2007
    Posts: 1,620

    BuiltFerComfort
    Member

    Hmmm... want to smoke the 5.0 / 335i people? Find a 400 big block Mopar, put in a 440 crank in it for 454 cubic inches of pure Mopar power. A decent cam, intake and headers and you get 500+ streetable HP and massive torque.

    (A small block Chevy will be cheaper, the economics of the SBC are undeniable. A small block Ford will fit the engine compartment best. A small block Mopar will be coolest and get you less crap from purists. Do whatever fits your budget.)

    Then get a Jeep 8.25 or Ford 8.8 rear and some new stock-looking wheels that let you run the old hubcaps...

    Tim Adams over at the P-15/D24 forum put a stout 383 Mopar big-block in one of his, he has a photo album somewhere and can tell you all about it. Looks like tons of fun.

    That forum is run as a hobby by one of the members and he's tired of spammers, so he has to approve each new arrival, so be patient if it takes a day or two. Great folks there, happy with both restorers and hot-rodders.
     
  14. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    thanks a billion tom. i"ll mkae sure to post pictures when i have something worthy to post. right now i just have pieces and a stripped body and chassis ready for some work.
     
  15. Youreviltwin,
    The simplest swap for that chassis is a Camaro. Yes, they are a little too wide on the front track, but if you're gonna bag it, get the narrow lowers when you buy control arms. I've got a 51 3W that's going a little different direction than the HAMB cares for...camaro stub, 383/4speed. Everything you're asking about is what I've done to mine (except bags).

    If you're interested, PM me and I'll send you a link to another site where I've got pics of mine.
     
  16. hkestes
    Joined: May 19, 2007
    Posts: 576

    hkestes
    Member

    I will throw in for keeping the stock front suspension with a couple of minor upgrades. I have rebuilt mine on my 48 Club Coupe which is my daily driver in and around Dallas.

    1) Rusty Hopes (AKA Olddaddy here on HAMB) disc brake kit. Drill and Tap 4 holes and from there it is a bolt on. GM Calipers and Mopar Rotors.

    2) Shock relocation pretty straight forward. There is a good tech here on fabbing the brackets and installation

    3) If you are going with a V8 would highly recommend a swap to Rack and Pinion. Fatman has a kit for this as do a few others. The stock box can be a real pain when trying to shoehorn the V8 into the frame rails.

    No need to go the frame swap or subframe route. It involves a bunch of work for minimal gain compared to the 3 mods mentioned above. It is also work that if not done exactly right could doom the project completely.
     
  17. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    i see what you all are saying and i appreciate all these different routes i can go. i was almost stuck thinking id have to reinvent the wheel here and its great to know plenty others have already done this.

    my biggest concern is out of all these set up what do you guys that have tried these different set up think is the best suspension geometry and set up that will alow the car to handle the best it possibly could?

    im not building some crazy pro-touring hot rod i just want to build something i can at least try to hang with my buds and there new school plastic hot rods.

    i will be looking into all of the forums and websites mentioned here. thank you guys very much for some well needed directions. feel free to share as much as you care to. if ya'll were close by id buy ya a round. cheers!
     
  18. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,535

    50dodge4x4
    Member

    I've read everything that has been said here. Sounds to me like you want to go fast with an old car without spending any money. Simply isn't going to happen. That Plymouth is a 3,000 lbs car, If you expect it to "hang" with your buddies built up ricers that weigh 1/2 as much, you better expect to spend some money. Do you really think that nearly 70 year old frame is going to be up to the task of competing with an upgraded 10 year old chassis?

    The original 48 frame and suspension can be made to work well on a moderately driven street car, but a race car it won't be. You can add as much horse power as you wish, the frame and chassis can probably handle it if its still solid and rust free, but if you expect it to handle as well as a sports car, your going to be unhappy. Sorry.

    If you really want it to handle like a sports car, you need to upgrade it to a sports car frame and suspension. Someone above suggested a Camaro frame, that is a step in the right direction, for what you want. Unless the Camaro is way too wide, I'm not sure I'd try to narrow it up much, wider handles better on curves. You will also need to upgrade the rear suspension and brakes, and swap in a more heavy duty rear axle. A good handling car is a whole package, not just one end. Pretty much anything with air in it , other then tires, does not help in the handling department, air compresses to easily.

    Once you get the handling and brakes under control, your drive train has to work as a package as well. If you expect to kick all your buddies butts, you better come to the test ground prepared to go fast, turn fast, and stop fast. Being fast is not cheap, and its not something you can do if your going at it half ass. You don't need the latest trick thing, but you do need a solid foundation. Fast is in the chassis and drive train. The body just covers all the important things, and the latest trick stuff just adds to the cost.

    I suggest before you begin you do some reading on what it takes to make a car handle, there are some really good books on the subject out there.

    Now, if you were looking for a great street car to cruise around in, that is a different story. Understand, everything is a compromise, to get something, you have to give something else up. Decide what you really want before you begin. Gene
     
  19. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    thanks gene. yea i do understand what it takes. i just didnt know if with a front end like a mustang II with bigger brakes, along with a boxed in frame and rear c-notch would be enough to make it handle as well as possible and also adding some bracing in the rear of the frame to keep it strong and firm.

    in regards to using air i will be using ride tech showckwaves with dampening and rebound adjustments i believe 16 way each. i feel confident with that air suspension for performance being the cars they have set up and ran on tracks.

    im just wondering if hacking up and modifying this frame is a better deal in regards to loot and time than swaping it for a more modern frame that will still need c-notching and possible rigidity added to it.


    i feel comfortable with the 8.5 inch grand national diff. a good set of mosr axles will be enough for the moment.

    ive seen g-body 7.5 with an auburn posi, some aftermarket axles and slicks take some abuse. granted i do not know how long it will last i feel safe with it as long as i take those precautions.

    3000 or so lbs, with a small block were pushing to squeeze 350-400 out of it with a 200 shot is ok with me as long as i have a manual gearbox.

    im not out to build some crazy hot rod race car. i just want to compete with my bud mustang and a 3351 which is similar in the weight and give or take hp.

    thats why once i have the engine/ trans/ and chassis under control and in the works gearing between the final drive and overall wheel circumference will be addressed to get as much out of it as i can.


    thanks for your input it makes all the sense.
     
  20. farmer12
    Joined: Aug 28, 2006
    Posts: 7,716

    farmer12
    Member

    Sounds like you're getting plenty of ideas here. I would definitely go with a disc brake set up, like some guys have pointed out. Shockwaves may be difficult, but normal bags on the front is no problem. When I bought my car, it had bags on the the original front suspension which worked good. I went one step further and cut the front end off. Extended the frame and installed a m2 with shockwaves. You'll need to spend some decent money on this, not sure if you want to go this route. If you want to stay with the old front suspension , do the rack and pinion set up.Engine wise, there is enough room under the hood to fit something decent, some fabrication is required though. Check out my build thread (41 plymouth coupe 392 hemi), maybe this will give you some more ideas and thoughts.

    Post some pics if you can and good luck with the decision making process. Farmer12
     
  21. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    yea thanks for the great ideas guys. i have had alot of reading to do with all these different directions you guys have sent me and have learned quite a bit about the possibilities of what can be done with this chassis.


    so far im thinking i will notch the back and link it to work with the diff i want to use and lay down and handle like itd like it to.

    as far as the front im still torn im thinking if anything i can use the stock front with the shock relocators, use some bags and adjusting shocks with a disk brake kit and see how that handles. im curious to know something else. those who have used the stock front end of the frame and suspension. where in relations to the fron suspension does the engine sit?

    does it sit on top of the front arms half way or is it pushed behind the fron suspension closer to the firewall.

    im trying to get a better idea since all i got from pops was a stripped rolling shell. it does have the stock inline six and it looks like it sits considerably back behind the front suspension but cant compare that to a small block and the room it will take up.
     
  22. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl


    i was looking at yout thread last night and dont know if you posted it and i missed it but may i ask the reason behind extending the frame two inches?
     
  23. farmer12
    Joined: Aug 28, 2006
    Posts: 7,716

    farmer12
    Member

    I extended it in the front because I will need some mounting points for the front/grill assembly. The big bar in the front will also give me some frontal impact protection as well as stiffness to the frame. The original radiator used to mount on the front suspension, but considering all of that is gone now, new mountings will be fabricated on the newly extended frame. Hopefully I've answered your question.
     
  24. Little Wing
    Joined: Nov 25, 2005
    Posts: 7,504

    Little Wing
    Member
    from Northeast

    Whats so wrong with the stock frame , its a health frame ?? Also a 8 3/4 rear comes in several sizes
     

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    Last edited: Jun 11, 2010
  25. youreviltwin
    Joined: Oct 21, 2008
    Posts: 69

    youreviltwin
    Member
    from fl

    yea farmer makes sense. thanks again.

    little wing. thats the thing i didnt know how worthy the stock frame could be. i want it to perform quite well and be ale to whip it around the streets with occasional autocrossing and some drag strip time. im not trying to build the ultimater race car but something i can bring around my buddies new 07 beamers, mustangs, subarus, and evos and hold my own bringing them shock when they see this 62 year old car hanging with or hopefully handing it down to their new technologically advanced tuner cars. all that and i want it to look kind of ratty like i found it in a barn, threw some wheels and bags on it an called it a day.

    its unfortunate the group of folks i hang around with are all about whats newest and the latest in tuners. im trying to show them otherwise.

    therefore i am trying to make the best decision i can to have the best handling, stiffest frame, and shed some lbs. while im at it so i can hold my own around them and represent for our kind of folks here.

    thanks.
     
  26. OK enough of the crap, stock front with disc, r&p, relocate shocks. rear jag ifs works great. now you have 4 wheel independent suspension 4 wheel disc brakes. run a nice 360/904 (or 518 if you want od) it will be a nice power to weight ratio. and you will put the wanna be boys in the dust. by the way these don't weigh no 3000# more like 2200#.
     
  27. 73RR
    Joined: Jan 29, 2007
    Posts: 6,708

    73RR
    Member

    Short of plopping the body onto a Corvette chassis I really do not believe that you will ever have a 48 Ply that will keep up with a 3 series BMW on any road course.
    Also, using a sbc and a t-56 indicates high rpm line of thinking but the t-56 is not cheap. For the $2500 that a t-56 will cost I second the thought to use a B-RB and build some monster torque instead of needing alot of gears.

    My NADA Classic Cars price guide shows weight right at 3000 lbs.

    .
     
  28. What?! :eek: You think mating a 50 year old rear (iRs) suspension design with a 60 year old chassis is going to make it run with a new KIA, let alone a Beemer or Evo?

    Buy a hat.
     
  29. rockable
    Joined: Dec 21, 2009
    Posts: 3,784

    rockable
    ALLIANCE MEMBER

    It will ride well and steer reasonably well with the stock suspension. It will never handle like a sports car because the suspension is 70 year old technology. If you're willing to accept that, then keep the stock suspension and upgrade it. If not, get out your pocketbook because you're going to have to upgrade the front and rear suspension.....both.
     
  30. Have you ever driven one? or just talking out your ass. they will do pretty well. by the way a schwinn 3 wheeler will handle better than a kia.
     

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