225 to 318 or 440 swaps

[48dodge]

Here's the question first, what are the major hurdles in swapping slant six to 318 or 440 in a 65 to 68 fury or polara ?
Now the long winded story to go with it., I have the bug bad and there are some 65 68 4 door fury's in the area, nice condition, minty ,but plainish , grandpa cars . which is even cool in some ways , 40 , 60 thousand mile cars .. Plus a 67 4 dr polara , 60 thousand , all with auto slant sixes all reasonably priced. And in between Also a sharp fury 3 again 4 dr , but with a 383 commando, ( tempting)
Nice 2 doors are 4 to10 times the money.
Rusted out ones, beat up interiors ones are still double .the price of these.
I would gladly drive the slant sixes, and it will take a few years anyway to get any of the swap possibilities, rebuilt to drop in .
Here they are , already have them
Potential swaps, 72 b body 318 and auto.
Runs drives sounds great ,
71 440 out of Chry 300 , and trans will have to rebuild the motor ok but sat too long . And the rads and accessories out those cars are all there.
So what are the main hurdles trying any of these swaps,
Front suspension? Motor mounts ? Transmission extension lengths,
I am tempted to snap up one of these any way , but swap potential gives me more excuses to explain away another car.

 

[CBODY67]

As all of these will be "production-based" changes, they CAN be somewhat easier to do than putting something else in the engine bay, BUT each engine combo has it's own unique-to-them items on the REST of the car. Like appropriate suspension upgrades to handle the weight (think torsion bars and rear leaf springs, plus brake shoe/drum widths) and power (different variations of TF and rear axle ring gear sizing). Then there are the wiring harness differences in the engine bay and which side the exhaust system is run on (as in rh side or lh side rear exits). And, the issue of whether or not the front suspension got an anti-roll bar (std on B/RB cars and optional on others). Lots of little things in addition to the other bigger and somewhat more obvious things, other than just having the correct stub frame mounting brackets and the matching engine-side motor mount brackets.

NOT saying they are not doable, just that there are lots of other related things involved, too, by observation. Best to have the donor vehicle and receiving vehicle side-by-side or nearby, generally. Which can mean "garage space to work in". Along with adequate longer-term funding availability so that "life" might not cut the projects short in the process.

Just some respectful thoughts,
CBODY67

 

[48dodge]

Well I knew there was more to it than i could imagine, i have dealt with drive shaft differences, swapping a 71 300 440 motor and trans Into a 70 383 newport. Good point about a donor car.
That would take care of a lot of it.
Except the work part.
I have done the rust thing on one car . That's enough. Same with interior unobtainable stuff cracked dashes , seats ,headliners. mechanical is a little more understood, in my case and I have the facilities. Space and time to find a donor.
Smallish investment , 2,-4 thousand., and still get to drive it , while gathering the pieces.
Thanks food for thought

 

[Big_John]

The best place to start with figuring out the differences in mounts etc. is to look at the parts manuals for the car in question. Download one (or more) here: Resource Library – MyMopar

 

[Davea Lux]

For starters, the stub frame on a 225 is different than all V-8 engine mounting systems. You will need to locate a V-8 stub and install it to start the conversion process. As noted above, a donor car is the best way to do the conversion. The '65-'68 Fury's and Polara mostly had 8.75" rear ends. The springs and brake drums are going to be different for a big block car. The front yoke on the rear end is also lighter on 6 cylinder equipped cars. Transmissions will not interchange. 6 cylinder transmission is unique to the 6cyl. The 318 uses a small block transmission, B and RB engines use a heavy duty 727. The radiator is also different. Front brake drums are also narrower on the 6 cylinder cars and a lot of them did not even have power brakes. The light duty brakes that come on a 6cyl car are not adequate to stop a large V-8 powered beast.
If you have the donor car, you can swap out the rear end, rear springs, stub frame and start bolting on everything else. On this type of conversion, it is usually the small stuff that drives you crazy, stuff like mounts for the various accessories, shift linkage, throttle linkage etc, you will always want the donor close by. Been there, done that, don't want to do it again.

Dave

 

[livininharrow]

just a thought. you can make real nice power with a built up turbo slant and they look cool when done right.

 

[twostick]

As has been stated, /6 uses different motor mount frame brackets than the V8 cars but I can't imagine that the stub frame is different in any significant way. Given the very small percentage of /6 production, you would make the engine fit the stub frame, not the other way around. Small block and big block use the same frame mounts. 65 has a one year only orphan left mount. Avoid it if you can. I don't know if there is any difference other than the bracket between a 65 stub and a later one.

If you have fabrication skills and tools, you should be able to carefully remove the /6 and V8 brackets and then install the V8 brackets to the /6 stub.

/6 brakes should be a none issue because you're going to swap in a set of 69-73 disc spindles anyway, right? lol

Torsion bars. Keep in mind a Plymouth bar is 44" long and the rest are 47". That might cause a problem if you were thinking of swapping stub frames into or out of a Plymouth to a Dodge or Chrysler or vice versa. If you plan to do any drag racing activity, the /6 bars with 90/10 front shocks are the best bang for the buck for weight transfer and traction. Crank them right up to get something approaching normal ride height and when you wack the loud pedal they will rotate the front of the car up instantly. NOT the hot ticket for corner carving but more than up to the task of cruising or driving to the track...

PST lists 1.12" bars for Plymouth and Dodge/Chrysler if handling is more the focus.

Suspension - Coil Springs/Leaf Springs/Torsion Bars - Torsion Bars!

Power and manual brakes use their own respective brake pedal assemblies.

Rear axle in a 65 to 68 will be an 8.75 regardless of engine with the exception of some 4 speed cars that had a Dana 54. I think the 8.75 was phased out in 72 or so. Backing plates and brakes from a Chrysler will get you the 2.5" wide shoes and drums.

Nigel at National Moparts in Beaverton Ont. is an excellent resource for all things C body.

National Moparts

Kevin

 

[tim howe]

318 Poly used a 727 trans, I have one with a 727 that came out of my 66 Sport Fury, OEM.

 

[Davea Lux]

318 Poly used a 727 trans, I have one with a 727 that came out of my 66 Sport Fury, OEM.

727 transmission for '62 and up 318 poly and '67 up c-body LA series 318 share the same bell housing but they won't bolt up to B or RB series engines.

Dave

 

[Davea Lux]

As has been stated, /6 uses different motor mount frame brackets than the V8 cars but I can't imagine that the stub frame is different in any significant way. Given the very small percentage of /6 production, you would make the engine fit the stub frame, not the other way around. Small block and big block use the same frame mounts. 65 has a one year only orphan left mount. Avoid it if you can. I don't know if there is any difference other than the bracket between a 65 stub and a later one.

If you have fabrication skills and tools, you should be able to carefully remove the /6 and V8 brackets and then install the V8 brackets to the /6 stub.

/6 brakes should be a none issue because you're going to swap in a set of 69-73 disc spindles anyway, right? lol

Torsion bars. Keep in mind a Plymouth bar is 44" long and the rest are 47". That might cause a problem if you were thinking of swapping stub frames into or out of a Plymouth to a Dodge or Chrysler or vice versa. If you plan to do any drag racing activity, the /6 bars with 90/10 front shocks are the best bang for the buck for weight transfer and traction. Crank them right up to get something approaching normal ride height and when you wack the loud pedal they will rotate the front of the car up instantly. NOT the hot ticket for corner carving but more than up to the task of cruising or driving to the track...

PST lists 1.12" bars for Plymouth and Dodge/Chrysler if handling is more the focus.

Suspension - Coil Springs/Leaf Springs/Torsion Bars - Torsion Bars!

Power and manual brakes use their own respective brake pedal assemblies.

Rear axle in a 65 to 68 will be an 8.75 regardless of engine with the exception of some 4 speed cars that had a Dana 54. I think the 8.75 was phased out in 72 or so. Backing plates and brakes from a Chrysler will get you the 2.5" wide shoes and drums.

Nigel at National Moparts in Beaverton Ont. is an excellent resource for all things C body.

National Moparts

Kevin

If the op is going to pursue a donor with a V-8 stub, it will just make more work to change the mounts. An air chisel can be used to knock of both sets of mounts. The welds to attach the V-8 mounts need to be very good quality and properly placed to avoid breakage. Probably simpler to just unbolt the stub with the front tires attached and roll it out of the way. Replacement stub can be installed by reversing the process.

Dave

 

[twostick]

If the op is going to pursue a donor with a V-8 stub, it will just make more work to change the mounts. An air chisel can be used to knock of both sets of mounts. The welds to attach the V-8 mounts need to be very good quality and properly placed to avoid breakage. Probably simpler to just unbolt the stub with the front tires attached and roll it out of the way. Replacement stub can be installed by reversing the process.

Dave

For some reason I though the OP was from Ontario, making bolt removal for the stub swap potentially impossible but a Saskatchewan car should be almost a slam dunk.

That being said, it's still a big job. I think if you have the fab skills and equipment to change the mounts properly, it would be a lot less work, physical labor wise to do that.

Kevin

 

[MAXWEDGECHAR]

In 1972 my dad wrecked our '68 Custom Suburban. I took it and replaced the stub frame with one from an NYer with new HD torsion bars. I was going to replace the 318 with a 440 but it never happened. The car sat like it was under acceleration all the time! Then I needed a trans and a friend had a 904. And yes they built C-Bodies with 318s and 904s. I looked into my parts book archive and found what cars used the same driveshaft. I haunted junkyards for weeks until I went back to the place where I got the stub with my tape measure and there was a driveshaft marked " '68 PLY WAGON"! It was the correct length.

 

[48dodge]

That is a lot to absorb, certainly gave me an idea. Really interesting , thanks for your time .