Possible Drivetrain Swap 48 Plymouth 4-Door

[jrodenbucher]

Hello folks! I am just getting started on this wonderful journey of building up my first car! I picked up a 1948 Plymouth Special Deluxe 4-door from my uncle who bought it sight unseen when he was sh*tfaced several years back. The last time it ran was in the early 1970's and had been kept in a barn in Puget Sound-area Washington ever since. Needless to say, it needs work. Now, I've been doing as much research as I can regarding standard issues with this model and I have a pretty good idea of where to go. However, a friend has just made me an interesting offer. Now, this may offend some of you, but I'm not very picky about keeping it strictly mopar. I just want a ride that is comfortable, reliable, and performs decently; it doesn't have to be outrageous. Anyways, a friend offered me the entire drivetrain, including motor and transmission, out of his 1984 Z28 Camaro if I swap a 350 I have lying around into his Camaro. Now, I've swapped a few motors out before and this is no issue, however, upon doing a bit of research, I noticed that the Z28 Camaro and the 1948 Special Deluxe have nearly identical wheelbases. What I'm wondering is, how difficult do you think this would be to make this work. I would essentially be swapping front-end, motor, trans, and rear-end out of this Camaro. Do you think it would be possible to do without having to do major damage/mods to the frame? Thank you so much for your time and knowledge!

[knuckleharley]

It is possible to use the Camero rear end and the transmission with only minor modifications,but replacing the Mopar front suspension with a Camaro suspension requires you to cut the Plymouth chassis off just in front of the firewall and weld the Camaro frame clip to the stubs. If you are confused by words like "track",rake,frame reinforcement brackets, and "ride height" don't even think about the front frame clip swap. Don't think about this swap unless you are a good enough welder to turn pro and have a good welding machine,or plan on just tacking it together and having a pro do the final welding.

 

Or at least this was all required with the 78 Camaro suspension  swap into my 48 coupe. The 84 is different than the 78,but I don't know what the differences are or how they will will apply.

 

My best advise is to forget the frame swap and just rebuild anything in the stock front suspension that needs to be rebuilt. There is nothing wrong with the way these cars ride or drive with the stock front suspensions,and that's a lot of work and it involves a pretty steep learning curve.

 

Arthur

[BobT-47P15]

Just use Rusty Hope's front disc brake conversion kit to improve braking.  And re-mount the front shocks with a set of

arms off a Ford pickup (or, I think, a Dodge pickup).  Or Rusty Hope also offers those mounts.  If the coil springs are

weak or sagging, you can replace them.  If you want to lower the front, simply cut one or one and a half coils off.  

 

Don't know if any cutting of the cowl would be needed with that engine setup.  The engine usually has to be offset

to the passenger side a couple inches to clear the original steering box.  I'm no expert......just passing along things

others have said.

[GlennCraven]

Butch's Cool Stuff, a banner advertiser on this site, has a $299 engine-swap kit that should work even if keeping factory steering. Just ask for the one with one-inch off-center mounts to clear the steering box.

 

My biggest question is: If the 350 you already have is apparently a better mill than the engine already in your pal's Z28, why not put the engine you have lying around into your own project?

[falconvan]

Id have to agree with Arthur on the front end. I've seen a 47 with a Camaro subframe and it wasn't pretty. The frontends on these are good, just relocate your upper shock mount from the A-arm to the frame and rebuild what needs it. As far as using an SBC; should be easy as long as you can weld, fabricate some mounts, and possibly handle a little firewall surgery. I've seen several of these old Mopars with Chevy motors.

[Andydodge]

Or you can keep it all mopar like mine..........lol.......318 Poly, auto, original style front end  with rack & pinion, large sway bar, 4 wheel discs etc............and the steering wheel is on the wrong side....lol..........your car, your choice but a frame swap is generally more work than required for a nice riding updated old car...........regards, Andyd

[jrodenbucher]

Well, thanks for all the information folks! I think I have a pretty decent idea of where I need to start. Yeah, after hearing all the damage I'd need to do to replace the front end, I'll probably just rebuild what I have and throw some disc brakes up front. As to the question posed by GlennCraven: My friend was looking for a 350 to build up into a 383 and put a stroker kit into. The 305 also has the Corvette heads on it and performs amazingly. 

[greg g]

NOt to mentions fabricating all the mounts for sheet metal, bumpers etc.

[knuckleharley]

Well, thanks for all the information folks! I think I have a pretty decent idea of where I need to start. Yeah, after hearing all the damage I'd need to do to replace the front end, I'll probably just rebuild what I have and throw some disc brakes up front. As to the question posed by GlennCraven: My friend was looking for a 350 to build up into a 383 and put a stroker kit into. The 305 also has the Corvette heads on it and performs amazingly. 

BTW,I forgot to mention that the 350 engine will sit right up against the firewall,and every BTU of heat the engine puts out will radiate right back into the passenger compartment unless you recess the firewall. Even if you use the old-style short waterpump from the 50's and 60's, and don't run a fan on the end of the waterpump. Also,if you run a stock GM HEI distributor you will need a BFH to indent the firewall for distributor cap clearance. A Mallory or similar HEI distributor will clear ok,though.

 

I'm swapping out my worn 305 and junk turbo 350 transmission for a balanced and blueprinted 412 small block that borders on radical,and either a built turbo 350 with a shift kit,or a modified 700R4. Mostly because I already have them,and the 412 came out of another project and only has around 20k miles on it. I can't sell it to anybody without losing my  butt,so I might as well use it.

 

And while the engine and trans in it now are out,I will be grafting the recessed firewall from a 56 Ford pickup to the P-15 firewall,and make sure I have at least 2 inches clearance between the firewall and the engine heads. I may have more due to the deep factory recess already in the 56 pu firewall once I start blocking it up,and that will be ok with me,too.

 

This is the second car I have had with the engine almost touching the firewall,and I can tell you on a hot summer day if you get stuck in traffic it can be unbearable.

 

BTW,unless you spring for a custom radiator that you can fit further forward,recessing the firewall is your only real option. I'm using original P-15 tanks with a modern core in mine and it cools ok,but there is a limit to how far you can push it forward because of it's width and how the cars narrow at the front of the hood.

 

Another option if you just want a car to drive is to opt for a 4.3 V-6 Chevy engine,or it's Mopar counterpart. Lots of these modern V-6's make stupid horsepower while idling smooth and getting 25+ mpg. The new Mustang V-6's have 315 hp in stock form. Not much demand for these engines either,so you can pick them up pretty cheap at junkyards . Just make sure you get the transmissions and every bit of the wiring harness connected to the engine and transmission that you can find,along with the factory computer.

 

Arthur

Edited August 31, 2013 by knuckleharley

[Andydodge]

We all have different ways of doing things but all I can say is that if you have a look at the engine pic I posted above( and the attached pic) of my 1940 Dodge you can see that the firewall is NOT recessed at all and this is for a 318 Plymouth Polysphere V8, an engine that is much wider and longer than a SB Chev.......I mounted this engine myself 40 yrs ago...yep 1973......lol.........and its running fine even without an engine driven fan, no overheating due to a front mounted electric fan that has a manual override......the main consideration is actually the steering box and column and now that things like the Cavalier rack & pinion are available with a range of aftermarket steering uni joints there shouldn't be any real issue in installing these type of engines.........my 2 Oz cents worth.....Andy Douglas

[Scruffy49]

As much as I dislike GM products, we're going to a club show today in our 85 C10 short wide. The 4bbl 4.3L V6, TH350 and 2.73 rear gears gets 23-26 mpg. And is 32 cubic inches bigger than the large small block L6 (23" head 230). If I swapped in a later S10 Blazer sourced EFI 4.3/700R4, it would likely get even better mileage.

 

That said, both my Dodges are still Mopar powered. One has its original issue LA318/727 and 3.55 gears (whopping 9-11 mpg). The other has a 48 P15 218/3spd on the floor and 4.78 gears in the rear, slower than mud flowing up Mt Everest and about 12mpg the last time I drove it. Both are staying with Mopar engines, but the 49 is getting a modern rear end and a lowering job.

 

Run what you want in it, but have a thick skin if you go to the show at the Pierce County fairgrounds every summer. Last time I went there was a separate section for non-Mopar engined vehicles. And the people showing in it caught a lot of grief for "destroying" their cars/trucks.

 

I grew up in your neck of the woods. Run over to Hagen's Auto Parts on River Road, just west of Puyallup Toyota before you commit to an engine swap. They have everything you need to get the L6 running, and running well. Try it, you may decide you like the old flatty. If not, you can always swap it out later.

[bamfordsgarage]

... Lots of these modern V-6's make stupid horsepower while idling smooth and getting 25+ mph...

 

Arthur

 

Hey, even my Model T will go that fast!

[knuckleharley]

Hey, even my Model T will go that fast!

 LOL! Ya got me! Thanks for the heads up. I have edited my post to read "up to 25 mpg" now.

[bobjob55]

mine is a 48 4 door with a 3 1/2" chop .. front clip from a early chevy nova .. NO ,, i did NOT  chop up a good car ,, found it this way .. work was done nice ..a 350 with 350 t. h. going in .. at least i can get parts for it anywhere .. maybe a/c will also be a option ..

[Frank Elder]

mine is a 48 4 door with a 3 1/2" chop .. front clip from a early chevy nova .. NO ,, i did NOT  chop up a good car ,, found it this way .. work was done nice ..a 350 with 350 t. h. going in .. at least i can get parts for it anywhere .. maybe a/c will also be a option ..

I can get parts for a mopar 318/360 V8 anywhere too.......