Donor for 63 dart GT

-
O

omotz

Member
Joined
Feb 3, 2024
Messages
7
Reaction score
0
Location
Sacramento Ca.
Looking at a 1975 valiant four-door with a six cylinder and a manual floor shift. My question is will the drivetrain fit in my 63, engine, transmission, and rear end. thanks in advance for any replies.

IMG_0031.jpeg
 
Question does your Dart have a clutch pedal?
Are you buying the complete car?
It may have better brakes front and rear, possible disc with larger bolt pattern?
All parts will bolt in, you will have to use your engine and trans mounts & brackets and possible other things, just need more info to help you through it.
 
moparlvr166 said:
Question does your Dart have a clutch pedal?
Are you buying the complete car?
It may have better brakes front and rear, possible disc with larger bolt pattern?
All parts will bolt in, you will have to use your engine and trans mounts & brackets and possible other things, just need more info to help you through it.
Click to expand...
Yes, the car has a manual transmission already in it and I’m looking at the whole donor car. It is complete. Thanks
 
You can upgrade you brake system front and rear with master cylinder.
Do you know what rear end is in it? is it a 3 or 4 speed?
 
Is it a bolt-in? No. Is it at least do-able? yes, depending on your abilities and ambition.
There are many differences that will need to be addressed: Engine, transmission, rear end, suspension, and electrical.
Let's start with the engine.
The '75 engine will physically fit, but the following will need to be done:
You will need to use the engine mount brackets and insulators from your '63 on the '75 engine.
You need to use the '63 oil pan, pickup and dipstick; the early pan is slightly different to clear the early steering centerlink.
The throttle linkages are different, the '63 uses a rotating throttle rod and the '75 uses a throttle cable. You can work around this a couple of ways, either swap the intake and carb from the '63 onto the '75 motor, or swap the '75 pedal and cable into the '63 (not a direct bolt-in, some adapting is necessary. Easiest would be to locate a '64-'66 V8 throttle pedal assembly, which would bolt in to the '63 and uses a cable).
Ignition is different; the '63 uses points and can be swapped onto the '75 motor, or the '75 can donate parts of it's wiring harness, ECU and ballast resistor to retain the '75's electronic ignition.
Similar situation with the charging system; the '63 uses a mechanical regulator and single field alternator; the '75 uses a dual field alternator and electronic voltage regulator. Either retain the '63 parts or modify the wiring to update to the '75 parts.
Cooling system: you could retain the '63 radiator, or adapt the '75 to fit- but depending how it's optioned, the '75 radiator may require modifications to the '63's radiator yoke opening and radiator's mounting brackets.
Brackets, pulleys and accessories will need to be determined depending on how the two vehicles are optioned.
There will be other changes needed, I'm sure, but that's what occurs to me offhand.

Now the transmission.
You didn't specify what the two cars are- is the '63 a floor or column shift? Assuming the '75 is a floor shift, but is it a 3 speed, four speed or OD? The particulars of the swap will depend on the answers.
All will physically fit your '63, although any of the floor shift transmissions will require cutting the floor pan and installing a transmission "hump" to clear the linkage and shifter. '64-'66 cars (which would fit your '63) had different style humps than the '75, although it may be able to be adapted depending on your abilities and level of creativity.
Clutch linkage- The two years had different width frame rail spacings, so the torque shaft (Z bar, bellcrank, whatever you want to call it) is wider from the '75 and will require a bit of narrowing to fit the '63. The pivot locations on the frame and bellhousing also differ between the two years.
The transmission/driveshaft on the '63 uses a ball and trunnion front joint, whereas the '75 uses a splined output shaft and slip yoke arrangement. You will need to use the '75 style shaft, although both cars share the same 111 inch wheelbase, the driveshaft lengths are going to be a bit different due to the engine mounting location, so plan on having the '75 shaft shortened or having a new one made.
You will need to use a '66-'67 speedometer cable to connect the '75 transmission to your '63 speedometer, those are the only two years that have the correct fittings on both ends of the cable for this swap.

Rear end.
The '75 is *most likely* going to be a big bolt pattern 7 1/4. Fundamentally the same as your '63's small bolt pattern 7 1/4, pretty much a bolt-in with the possible exception of your parking brake cables; although you should be able to use the '63 cables or mod the '75s to fit. This will also give you 10" drums in the rear, an upgrade from the '63's 9" stockers. The biggest change is that you'll now have a 5x4.5" bolt pattern in the rear, which doesn't match your 5x4" pattern in the front. Which brings us to:

Suspension and brakes.
If the '75 rear leaf springs are in better shape than the '63, swap 'em in- they're the same size (the front and rear spring hangers are not the same, however).
Same goes for the torsion bars in front- they'll interchange if needed. But to get the front bolt pattern to match the rear, you'll need to do some swapping with the front brakes, too. With any kind of luck, the '75 has front disc brakes. To use them on the '63 you need to swap the upper control arms, spindles, lower ball joints and brake lines. Use the master cylinder, booster (if so equipped) and proportioning/combination valve from the '75. If they're still in decent shape, you may be able to re-use the appropriate brake lines from the '75 to aid in the swap, since the plumbing part of the brakes is totally different due to the double reservoir master and combination valve.
If the '75 has front drum brakes, you can still swap them on (same procedure as discs, above) and gain the 10" brakes, not as big of an improvement as discs, but an improvement nonetheless.
If the '75 has a front anti-sway bar, you won't be able to use it on the '63, as it will be too wide as well as being of the type of design that goes "through" the K frame rather than under it.

These are just a few of the basics, I'm sure others will chime in with any other details or things I may have missed. And a little clarification is needed as to the transmissions in the vehicles.
 
Last edited:
It would be 2025 by the time I typed all that!
Good Info. Me personally would try to adapt as much from the 75 as possible.
Good luck
 
I agree with everything Professor Fate said...HOW COULD YOU NOT? That is the wonderful thing about this site. KNOWLEDGE , HELP and BEEN THERE AND ALREADY DONE THAT! Congratulations that is a wonderful little Dart. I recently saw one for sale with a pistol grip 4 gear that looked like it came out of a Roadrunner. It was huge in that little Dart but you couldn't help but appreciate it...LOL
 
We would need to know the exact drivetrain that is in each car to give you further details.....especially if you're trying to mix and match components. If the '75 has drum brakes, it will have the same bolt pattern wheels as a stock '63. If it's got disc brakes, it will have the big bolt pattern front and rear, so, a wheel change in needed too. With any luck, it has disc brakes and an 8 1/4 rear which would be a recommended upgrade. I just got thinking...and there is another caveat to swapping the drum brakes from the '75. The stock '63 13" wheels will probably have clearance issues with the 10" finned front drums. Test try them first before you do the swap so you'll know what you're getting into.
 
Last edited:
Either way he'll have the wheels from the '75, which would be 14s- so at least he stands a chance of finding decent tires for those, as opposed to the 13s...
 
Professor Fate said:
Is it a bolt-in? No. Is it at least do-able? yes, depending on your abilities and ambition.
There are many differences that will need to be addressed: Engine, transmission, rear end, suspension, and electrical.
Let's start with the engine.
The '75 engine will physically fit, but the following will need to be done:
You will need to use the engine mount brackets and insulators from your '63 on the '75 engine.
You need to use the '63 oil pan, pickup and dipstick; the early pan is slightly different to clear the early steering centerlink.
The throttle linkages are different, the '63 uses a rotating throttle rod and the '75 uses a throttle cable. You can work around this a couple of ways, either swap the intake and carb from the '63 onto the '75 motor, or swap the '75 pedal and cable into the '63 (not a direct bolt-in, some adapting is necessary. Easiest would be to locate a '64-'66 V8 throttle pedal assembly, which would bolt in to the '63 and uses a cable).
Ignition is different; the '63 uses points and can be swapped onto the '75 motor, or the '75 can donate parts of it's wiring harness, ECU and ballast resistor to retain the '75's electronic ignition.
Similar situation with the charging system; the '63 uses a mechanical regulator and single field alternator; the '75 uses a dual field alternator and electronic voltage regulator. Either retain the '63 parts or modify the wiring to update to the '75 parts.
Cooling system: you could retain the '63 radiator, or adapt the '75 to fit- but depending how it's optioned, the '75 radiator may require modifications to the '63's radiator yoke opening and radiator's mounting brackets.
Brackets, pulleys and accessories will need to be determined depending on how the two vehicles are optioned.
There will be other changes needed, I'm sure, but that's what occurs to me offhand.

Now the transmission.
You didn't specify what the two cars are- is the '63 a floor or column shift? Assuming the '75 is a floor shift, but is it a 3 speed, four speed or OD? The particulars of the swap will depend on the answers.
All will physically fit your '63, although any of the floor shift transmissions will require cutting the floor pan and installing a transmission "hump" to clear the linkage and shifter. '64-'66 cars (which would fit your '63) had different style humps than the '75, although it may be able to be adapted depending on your abilities and level of creativity.
Clutch linkage- The two years had different width frame rail spacings, so the torque shaft (Z bar, bellcrank, whatever you want to call it) is wider from the '75 and will require a bit of narrowing to fit the '63. The pivot locations on the frame and bellhousing also differ between the two years.
The transmission/driveshaft on the '63 uses a ball and trunnion front joint, whereas the '75 uses a splined output shaft and slip yoke arrangement. You will need to use the '75 style shaft, although both cars share the same 111 inch wheelbase, the driveshaft lengths are going to be a bit different due to the engine mounting location, so plan on having the '75 shaft shortened or having a new one made.
You will need to use a '66-'67 speedometer cable to connect the '75 transmission to your '63 speedometer, those are the only two years that have the correct fittings on both ends of the cable for this swap.

Rear end.
The '75 is *most likely* going to be a big bolt pattern 7 1/4. Fundamentally the same as your '63's small bolt pattern 7 1/4, pretty much a bolt-in with the possible exception of your parking brake cables; although you should be able to use the '63 cables or mod the '75s to fit. This will also give you 10" drums in the rear, an upgrade from the '63's 9" stockers. The biggest change is that you'll now have a 5x4.5" bolt pattern in the rear, which doesn't match your 5x4" pattern in the front. Which brings us to:

Suspension and brakes.
If the '75 rear leaf springs are in better shape than the '63, swap 'em in- they're the same size (the front and rear spring hangers are not the same, however).
Same goes for the torsion bars in front- they'll interchange if needed. But to get the front bolt pattern to match the rear, you'll need to do some swapping with the front brakes, too. With any kind of luck, the '75 has front disc brakes. To use them on the '63 you need to swap the upper control arms, spindles, lower ball joints and brake lines. Use the master cylinder, booster (if so equipped) and proportioning/combination valve from the '75. If they're still in decent shape, you may be able to re-use the appropriate brake lines from the '75 to aid in the swap, since the plumbing part of the brakes is totally different due to the double reservoir master and combination valve.
If the '75 has front drum brakes, you can still swap them on (same procedure as discs, above) and gain the 10" brakes, not as big of an improvement as discs, but an improvement nonetheless.
If the '75 has a front anti-sway bar, you won't be able to use it on the '63, as it will be too wide as well as being of the type of design that goes "through" the K frame rather than under it.

These are just a few of the basics, I'm sure others will chime in with any other details or things I may have missed. And a little clarification is needed as to the transmissions in the vehicles.
Click to expand...
Great information thanks so much for the reply. The transmission I have is a three speed on the tree the transmission and the 75 is I’m guessing at three on the floor with what he’s telling me is a 225 six cylinder. It doesn’t look like a bulge on the left side of the tunnel that you would typically see on a force speed. The 63 has a tired 170 the non-synchromesh first gear three speed and a whining rear end so I’m thinking this could be a good donor car although the seller is’nt being very helpful with any questions I’ve asked. I live in Sacramento and the car is in Tucson Arizona a little ways to drive to check it out. I was hoping that he’d be more helpful. The 63 is fairly rust free, has some patch panels behind the front seat and spots in front as well. I’m guessing the floor pans are probably not the same so the Doner car wouldn’t be any help there.
 
Kendog 170 said:
It would be 2025 by the time I typed all that!
Good Info. Me personally would try to adapt as much from the 75 as possible.
Good luck
Click to expand...
Yes, great info to be had here and I think it might be 2026 before I finish typing all that LOL. And yes that was the plan to swap as much as possible.
 
I think I'd find a better place to store your bicycle though.... :lol:
 
Just be sure you "bag and tag" everything you take off of each car with some type of designation (ie 63/75, or Dart/Valiant). That way you don't get confused and frustrated when something does line up, or fit correctly. And take a "TON" of pictures before starting disassembly.
 
And keep a logbook of EVERY part you installed or modified- you'll be glad in a couple years when you have to replace something or do routine maintenance and "can't quite remember" which vehicle it came from...
 
So I got the guy with the car. I’m interested in to send me a photo of the fender tag was really tough to read so I copied it down on a piece of paper to the best of my ability. My 63 is a manual transmission car, three on the tree And the small six.

IMG_0901.jpeg
 
So I was hoping that somebody could help me with decoding the fender tag. Pretty sure it’s a 225 wondering if the three speed was full synchro or not and with the rear end being from an automatic how much difference does that make as far as gearing, compared to my 63. Again, thank you to anybody who takes their time to answer my question.

IMG_3862.jpeg
 
Stock should be a 903 transmission. 1st gear not synchronized. Probably the weakest of all the Mopar transmissions. Manual transmission cars generally came with a lower gear ratio in the rear end than an automatic. There should be a tag on it showing what it is unless someone took it off and didn't put it back on. You can pull the cover and look on the ring gear too. There's also a way to spin one axle shaft and count the revolutions of the drive shaft.
 
omotz said:
So I was hoping that somebody could help me with decoding the fender tag. Pretty sure it’s a 225 wondering if the three speed was full synchro or not and with the rear end being from an automatic how much difference does that make as far as gearing, compared to my 63. Again, thank you to anybody who takes their time to answer my question.

View attachment 1716230579
Click to expand...
Post up a good picture of the fender tag and will also need the 4 digit of the VIN so I know what assembly plant it was built at.
 
You must log in or register to reply here.
-

Back
Top