Hey, I hope this is the right place to ask this... I'm trying to turn my '41 Plymouth Bizzy Coupe into a fast and comfortable daily driver. I've read a little, mostly on this site, about using an "117 S-10 frame on these. Does anyone out there have any specific hints or info. on putting new frames under '40 or '41 Plymouths? Does anyone know of a better frame to use? Just getting started... Thanks
I'm no where near the authority on building cars, and I have never done a frame swap, but no one has answered, so I'll give it a shot. I have read numerous times that unless you have bucket loads of money and are extremely talented with welding and fabrication work DO NOT attempt a frame swap. I have also read that it is way easier to do upgrades to the frame that you have. I'm currently working on a 41 Ford business coupe. On my car, I changed the front cross member to one that would lower the car 2 inches. Then I completely rebuilt my front end with the addition of a Camaro power steering box, and disk brakes. I plan to start on the rear end mods this week end. There are a number of things you can do to your current frame that will be way cheaper and easier than a frame swap. Is your current frame in good shape? Doc
A friend of mine used an S-10 chassis under his '47 Dodge coupe. Fit like a glove and had the added advantage of every possible aftermarket suspension part being availible for it. The only real obstacle that he had to overcome was the steering column had to be relocated about a foot farther back and at a different angle, so a couple of steering U-joints were used. The car didn't have any floors or bodymounts left in it so all new ones were fabricated to line up with the new frame. I certainly would rather build new bodymounts and floorpans into a car (especially one that needs that stuff anyway) instead of trying to weld a front frame stub to the car and fab a rear suspension for it. Check out the Tech-O-Matic, there's a complete rundown on how to swap this frame underneath a 48-54 Chevy pickup. Looks straightforward enough, some of that info might be helpful and interesting to you.
If your frame is toast, or missing a lot of parts, I'd give this a lot of thought. Frame swaps and/or clips are not a good thing for someone "new" to the process to start with. If however your missing a bunch of stuff or your frame/ car floors are junk, its a different story. I have lots of questions you will need to figure out before you even start. What are your abilities? Can you weld and have the ability to fabricate? Do you have the equipment, or have access to the equipment to do the job? What drive train are you planning on using? Is the "finished" car going to be a cruiser or a balls to the wall street bruiser? How good are you at "finding" the parts you need? And, are you doing this yourself, do you have qualified help or payiing someone to help or do it for you? That 41 Plymouth came from the factory with a decent independent front suspension and a decent parellel leaf spring rear suspension. There are disc brake conversions available for your car, and many modern rear axles will fit on the leaf springs great simply by welding on spring perches in the proper location on the rear axles. I've even done a rack and pinoin steering on my 39 Plymouth (which is pertty much the same car). Gene
I would wholeheartedly agree. Try to work with the stock frame first. Your last resort should be a full frame swap. I speak from experience... Mercman
I have a 56 IHC 1/2T going together on an S-10 frame and while it wasn't as simple as throwing my cab at the frame and having it magically fall into place, it has been a relatively simple procedure. Now I have heard that trucks tend to be easier to do, but if your 41 coupe is in the condition my 56 was, it might be worth looking into. I had some minor damage to my frame and needed some floor work done anyway. After thinking it through, I realized that it was going to be no more work to do the swap than to just repair the damage. One other plus, S-10 chassis parts are cheap and they are everywhere. If I break down on a road trip, I can go to any parts store and ask for stock 87 S-10 brakes, shocks etc. Darren
Thanks for all the info, guys. I'm pretty torn. I know I can get a rollover S-10 for next to nothing. I'm no expert on welding or fabrication, but my dad and our friends are pretty good mechanics and we have a welder or two in the bunch. Tools are not a problem, and the labor would be cheap. I'm still feeling out just how much they want to take on with me and at what price. The current frame is straight and solid. The car still has an old 103hp, 230ci flat six motor (same type as original, but greater displacement). The powertrain is in fairly good shape (runs and drives). A good chunk of the front floorboard and a small part in the trunk have rusted out, and the brakes need serious attention (new wheel cylinders, pads, and who knows what else- we're taking a closer look next week). I want a car I can use as a reliable, long-term daily driver, preferably one that can cruise in at least the 65mph range. Do you think the current motor and tranny (non-OD) can perform that well? Would a swap to an OD tranny make that much difference? I have a fresh 350+ hp Chevy 327 with all the trimmings and a built 2004R tranny (Chevy bellhousing) that are begging to be used. I'm guessing that it wouldn't be all that hard to mount them to the current frame, but then I would definitely need power steering and disc brakes, and I'm guessing those would cost an arm and a leg. More than a frame swap? I guess it all depends. So, this is what I'm working with. Please, keep that advice coming... Zach
JMO, but in a word DON"T unless you have major fabricating skills, the stock frame is WAY strong enough and much less work to hot rod, kits are avail for disc's and sbc or mopar motor /tranny's + not real expensive and I would try it B4 you decide you need pwr steering , they are not that bad, I have it and am getting rid of it.My 46 is clipped and i wish it was'nt
I bought a disk break kit from speedway motors for 229. It took about 3 or 4 hours to attach a camaro power steering box to my frame. After market mounts to put a 350 and 5 speed in my 41 ford run me about 150. So that will give you a ball park figure at what your looking at. Doc
I've done this sort of thing three different ways. Upgrading the current frame would be my first choice. I'm kind of a junkyard guy so I would spend time adapting later components to upgrade my suspension. I'm not into using after market parts. My second choice would be to do a frame clip and install a later rear and springs. This retains most of the original frame and mounts.Not for anyone that doesn't have equipment and some good fabrication skills. Last would be a frame swap. not as involved as a clip skill wise, but you can count on major fab work in the floor and mount departments. Again not for anyone that doesn't have equipment and some good fabrication skills.
Zach, Your 41 business coupe is a pretty light car, 2850 lbs by the book I have. That big Mopar flathead 6 will haul it around pretty easy. By changing the rear axle to something more modern (which I would suggest) in the 3:20s - 3:50s gears, that 65 mph will not be an issue either. I just did a disc brake conversion on my 39 Plymouth. I did the firewall mounted 7" power brake booster, Corvette master, a new swinging brake pedel assembly, new porportioning valve, all new lines & hoses, the disc brake conversion kit (which consisted of the bolt on brake caliper bracket, the turned spacer, and bolts) and rebuilt calipers and new rotors (I bought USA rotors), wheel bearings and seals. The brakes on the modern rear axle were good. All that set me back about $1000, but everything is new or rebuilt. If I would have had some of the cores I needed I could have saved about $100, and I could have used the under floor master (but I didn't wat to) and would have saved about $400. So a disc brake conversion is around $500 all said and done for new stuff. Some one with some parts laying around and is good with a tourch and a layth to turn out the spacers could probably do a disc brake conversion pretty easy for little money. If the king pins are good in your front end, you may not need (or want) power steering. I put a power rack and pinoin steering on my car and I can tell yoyu that at 75mph the steering is a bit too easy. BTW they are great riding cars. Gene
Early Dakota front clip is about an easy a weld in as there is. R & P, disc brakes, same wheel bolt pattern. (note 4WD uses 6 lug bolts so not a donor) If you change the clip you will need to fab up some new sheet metal supports for the fenders inners and radiator. But prolly easier than fabbing a bunch of body mounts.
I dragged a Mustang II home from the boneyard and did mine, I will pay to have someone else do the next M-II. My 68 Chevelle should about drop in there. including the lower shock mounts. I went to Eaton Detoit Spring and they did mine, The goofy thing about those cars is the leaves are 1.75 inch wide, so you have to narrow the spring pads to get um to fit the springs. Yes the car does ride nice.
Where have you guys been all my life??? In the garage and at the track, I guess. Dumb question. Sunday I'm going to print this thread and dad and I will plot our game plan. I'll let you know what we decide, and I'll try to post a pic or two of the car. If we do decide to stick with the flathead and change the rear axle, what donor car should I look for? If I can, I'd like to keep the 5 x 4.5 bolt pattern (I have a set of 16x7 rims that would look nice on the ol' Plymouth). And isn't there a transmission or two with overdrive that will bolt onto the flathead? Keep that advice coming...
Zach, We've been right here, what took you so long to get here? My car has a rear axle from a Dakota pickup in it. The per 92s have 5 bolt on 4 1/2" pattern. You will probably have to reposition the spring pads on the axle. Most Mopar rear axles have the 5 on 4 1/2" pattern, just find one close in width. Some intermidiate Fords were 5 on 4 1/2" pattern too. Mopar did make and OD trans that would fit your flathead bell for several years around the 50s, Might do a want add in the "wanted" section od the classifides on here and one might turn up. Mopar used basicly the same flathead motor from the 30s until 1960. Gene
That is a key (among others) with a full frame swap. You have to MAKE a lot of the stuff since you can't use the originals off either car. Do a search for my name, and look at what I've been going thru for the past few weeks, or better yet click on the link in my sig for my (not so updated) website (my car has been in the works for years now) and decide for yourself. Alot of the issues with a full frame swap crop up AFTER you've already comitted yourself, and there's no going back; you have to make it work somehow. If you have a hoist, it will be much easier, initially...otherwise, you need a way to raise and lower the body MULTIPLE times while checking measurements to make sure you have the darn thing square. I went the affordable route for this, you can see how I did it (thanks to an idea from Leftturn) on my website. So much has to be fabbed, it makes it not worth it if there are suspension parts available to update your existing chassis. I have no way of mounting my front sheetmetal, for instance. It has to be built from scratch...as far as body mounts, if the donor chassis has good floors you can adapt, you won't need to worry about that...but if you start with a bare frame...it's another story. Add in the costs for all the stuff you have to buy just to be able to do the swap (if you don't own the stuff already) and you will probably come out ahead using your stock chassis and flooring. My .02 Feel free to PM me if you have any more Q's... Mercman
Measure your current rear axle and find something with the 5 on 4 1/2 bolt patern that comes close to the same width. I'm going to use a late model Ford Ranger pick up rear end in my 41 Ford business coupe. The ranger rear end is within an inch of my original rear end, it has 3.73 gears which should work well with my V8 and 5 soeed, it's a locking rear end, and it has disk breaks. The disk break kit I ordered for the front from speedway motors for the front also has the 5 on 4 1/2" bolt patern and it uses the older plymouth rotors. I do a lot of junk yard scrounging also. I found a 79 model Pontiac that originally had a 4 speed. I got the pedals, booster, and master cylinder from it. The cool thing is it looks like the bracket that bolts under the dash board that the pedals and booster mount to will be a bolt in instalation for my 41 after I drill a few holes in the bottom of my dash board and through my fire wall. The pedals from the pontiac also have the little chrome trim that goes around the out side edge. I know in the early model pick ups it is common to use the Volare front end to add power steering, disk breaks, and independent suspension. I have not heard of any one using it on old cars like ours, but you may go to a wrecking yard sometime and take some measurements just to see how close it comes. If one of those front ends will work for you, it will be a pretty straight forward deal to put one on your frame. This will also give you the 5 on 4 1/2" bolt pattern that your looking for. Has anyone seen this done on early model cars yet?
I'm glad everyone has pretty much gotten you straightened out, sounds like your car is in damned fine shape to retain the stock frame and drivetrain...one word of advice while you're deciding on keeping the stock equipment, take a hammer to the crossmember under the motor (right around the area where the lower control arms for the suspension mount to)...these are notorious for rusting out and since they're hot riveted in there they tend to be a pain in the ass to remove...other than some minor updates like a power brake booster and new wheel cylinders and possibly a rearend swap the stock components are more than strong enough to withstand daily driver usage...
You might also look in to a Jaguire front suspension swap. The whole front end of the Jag unbolts like a Volare suspension and mounts under your frame pretty easy. Also, with some carefull shopping those front ends can be had pretty cheap. I did some measuring on my 41 and a Jag, and they are realy close and I almost put one under mine, but the simplicity and durability of the straight axle is hard to beat.
Have you ever wondered why so my unknowledgeable guys think swapping frames is a good idea? Where do they get that idea? Too much television?
For rear ends that will fit your Mopar you maight wanna try these threads, lotsa good info: http://www.jalopyjournal.com/forum/showthread.php?t=88868&highlight=mopar+rear+axle http://www.jalopyjournal.com/forum/showthread.php?t=84474&highlight=mopar+rear+axle http://www.jalopyjournal.com/forum/showthread.php?t=91354&highlight=mopar+rear+axle Hope this helps, it did for me. I agree with the others, Mopars have strong frames (the old ones!), I'm using my frame with the stock front end with brackets from Fatman Fab to mount the upper shock mounts on the frame rails instead of the upper A-arms. For the rear, I'm looking for a '60's B body rear based on the info in the above threads. Several places can help with disc brake kits...check for some threads on places and folks's experiences. Good Luck
Late thirties mopars steer, ride and handle very well, even better when the front shock mounts are moved from the upper A arm to the frame. If your body mounts and floor pans are in decent shape it would be much less work to just convert to modern brakes and gearing/rear end and drive on. If its toast on the bottom side like most of the michigan mopars that I have worked on, then building new floors and body mounts makes a chassis swap worth doing. I opted to do suspension/brake upgrades to the 39 plymouth and 40 dodge that I had, I helped some on my uncles 41 coupe on a dakota chassis. The 41 coupe is new metal from bottom door hinges down (complete pan), the 39 and 40 just needed some holes patched in the floor, so there wasn't much to be gained by doing a complete chassis swap.
I build a lot of Mopars, and this is just my opinion, ok? I would not do a frame swap. Mopar has had very good ifs suspension since the 30s. I"ve got a car just like yours in my shop and I'm rebuilding the original suspension, relocating the upper shock mounts and installing disc brakes. That will be enough to go down the road at highway speeds without any real problems. You can install rack and pinion steering on the orignal frame if you want better steering. Your original frame is fine for highway driving. Other things you could do would be install a later model rear end for a better ratio gear and late model rear drums. If you are going to run the flathead on the freeway you will need an overdrive tranny or the rpms will kill the engine. If you want to go late model up front a Volare/Aspen suspension is the way to go for this car in my opinion. It's got ifs, good steering, discs, adjustable ride height and mounts for a V6, V8 or slant/6 already in place. So, keep in mind free advice is worth what you paid for it. If you want to go into detail on anything about your car, pm me. This is what I do day in and day out and I'm happy to talk about it with you.
Zach, My dad built a 40 Plymouth Business Coupe years ago. His recipe was all Mopar. Cordoba torsion bar front suspension (lots of fab work) 318 / 727, cuda rear end. The cool (easy) part was that the 8 3/4 rear out of a 70 - 74 Cuda/Challenger is a virtual bolt in to a 40 - 48 Plymouth. Just oval the locating pin holes on the spring perches inboard about a 1/4 inch per side and your done. The pinoin angle is close enough, but can be tweaked with shims if you want to. It's got a 235/70 tire on the back with no clearance issues. The Cordoba front end is a ton of work, but its bullet proof and rides nice. Personally, I'd call Fatman Fab and get a set of dropped spindles, disc brakes, and find a sway bar and maybe updated steering and call it good. Any V-8 is going to require modifications to the firewall. Don't go nuts, the 318 ony required a little, but we took our time and did a lot of finessing. The rad we used was a Nova (72-75 I think) stood on it's end. Cools fine with a low performance engine. Kept the stock e-brake and hooked it to the cuda rear, works great. A dodge dart 2dr (67-76) rear seat frame fits in the rear if you want to remove the package tray and allow space for passengers. A friend of ours that deals in a lot of fords remarked how he didn't like the way my dad's Plymouth rode and drove. He said it drove like a new car and didn't wander, shudder, creak, and bounce like his old cars do. And keep the original frame. Have you looked at the stock x-member. It's built like a tank! Good Luck. Scott
not sure if all models came with a sway bar, but I have the entire sway bar setup off of my '40 Plymouth I'd be willing to part with if yours doesn't have one already...and I've also got all of the front suspension parts stripped off of the car already if you happen to need any replacements parts like a-arms or springs, etc...I'm switching to a straight axle frontend in my '40 2 dr sedan and slapping a 331 hemi into it this summer, should be a fun car when it's all done next year...
Thanks again for all the advice! Looks like I need to read up on just what can be done with a Chrysler flathead 6. Any good stories or advice?
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