‘73 Duster /6 to 318 Swap

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Ratty73Duster

Ratty73Duster

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Hi everyone,

So, I’ve got a ‘73 Duster with a 225 /6 and 904 trans. I’m going to look at a nice 318 LA tomorrow and I’m planning on sticking a 727 in place of the 904. From what I’ve read, the Schumacher swap mounts are the easiest route, and require the least amount of work to the K-frame.

Would it be better to just find a v8 K-frame, opposed to using the Schumacher mounts? Also, what all would it take to convert the factory column shift auto 904 to a 727 floor shift? Any major modifications to accommodate a floor shifter?

This is a kind of learn-as-I-go project, so it’s a bit ambitious. Any help would be appreciated!

-Eli.
 
Ratty73Duster said:
Hi everyone,

So, I’ve got a ‘73 Duster with a 225 /6 and 904 trans. I’m going to look at a nice 318 LA tomorrow and I’m planning on sticking a 727 in place of the 904. From what I’ve read, the Schumacher swap mounts are the easiest route, and require the least amount of work to the K-frame.

Would it be better to just find a v8 K-frame, opposed to using the Schumacher mounts? Also, what all would it take to convert the factory column shift auto 904 to a 727 floor shift? Any major modifications to accommodate a floor shifter?

This is a kind of learn-as-I-go project, so it’s a bit ambitious. Any help would be appreciated!

-Eli.
Click to expand...
I would plan on finding a V8 K frame. Schumacher mounts are GREAT but there's something going on with the guy and his business and he's been WAY WAY behind in stock. Almost everything he was making is sold out and on back order and has been for well over a year or more now.

If you go the V8 k frame route, make sure you grab the pitman arm that attaches to the V8 K, the slant ones are different. Otherwise, everything else will bolt in just fine. You may want to see what rear axle is in your duster. If its the 7.25, you'll need to upgrade it to at least an 8.25 as the 318 will likely break the 7.25 if you get hard on it.
 
Ratty73Duster said:
Hi everyone,

So, I’ve got a ‘73 Duster with a 225 /6 and 904 trans. I’m going to look at a nice 318 LA tomorrow and I’m planning on sticking a 727 in place of the 904. From what I’ve read, the Schumacher swap mounts are the easiest route, and require the least amount of work to the K-frame.

Would it be better to just find a v8 K-frame, opposed to using the Schumacher mounts? Also, what all would it take to convert the factory column shift auto 904 to a 727 floor shift? Any major modifications to accommodate a floor shifter?

This is a kind of learn-as-I-go project, so it’s a bit ambitious. Any help would be appreciated!

-Eli.
Click to expand...
here's a good write up for you.


A-BODY ENGINE CONVERSION
 
easiest way to go to a floor shifter is to put an aftermarket ratchet shifter in there
keep in mind the 727 needs a shorter driveshaft then the 904


dukeboy_318 said:
the 318 will likely break the 7.25 if you get hard on it.
Click to expand...


this i doubt

but since you need to cut the driveshaft anyway for the transmission, it makes sense to swap out the rear end (if you decide to do so) at the same time, and only cut the driveshaft once
 
I've done this swap a few times, and most recently in a '74 Duster. I've swapped K frames and used the Schumacher mounts.
  • Mounts - You are correct, Schumacher mounts are the easiest, though swapping K frame isn't too bad. I used Schumacher on my current '74. I guess I'd do what you have easiest available.
  • Transmission - If you go 727, the shift linkage you have will work, but the slant 6 kickdown will not. You have lots of options for kickdown including Lokar cables or even using easy to find 318 2bbl kickdown (yes, it will work with a 4bbl pretty easy). Keep in mind, if you go with the 727, you'll need a different drive shaft as the 727 is longer. You will also need a 727 torque converter. IF you used a V8 904, it would be a direct bolt in.
  • other things to consider - radiator and exhaust?. Side note, the wiring harness and throttle cable will work from the slant to the V8.
 
dukeboy_318 said:
I would plan on finding a V8 K frame. Schumacher mounts are GREAT but there's something going on with the guy and his business and he's been WAY WAY behind in stock. Almost everything he was making is sold out and on back order and has been for well over a year or more now.

If you go the V8 k frame route, make sure you grab the pitman arm that attaches to the V8 K, the slant ones are different. Otherwise, everything else will bolt in just fine. You may want to see what rear axle is in your duster. If its the 7.25, you'll need to upgrade it to at least an 8.25 as the 318 will likely break the 7.25 if you get hard on it.
Click to expand...

Thanks for the info! I reckon I’ll just find a v8 K-frame, shouldn’t be too hard to find. Also, the car does have a 7.25 rear end, I’ll find a good 8.75 to go in place of it.
 
diymirage said:
easiest way to go to a floor shifter is to put an aftermarket ratchet shifter in there
keep in mind the 727 needs a shorter driveshaft then the 904





this i doubt

but since you need to cut the driveshaft anyway for the transmission, it makes sense to swap out the rear end (if you decide to do so) at the same time, and only cut the driveshaft once
Click to expand...

Thanks for the reply! And yeah, that makes a lot of sense. Swap the rear end now and not have to do anything further to the driveshaft.
 
318willrun said:
I've done this swap a few times, and most recently in a '74 Duster. I've swapped K frames and used the Schumacher mounts.
  • Mounts - You are correct, Schumacher mounts are the easiest, though swapping K frame isn't too bad. I used Schumacher on my current '74. I guess I'd do what you have easiest available.
  • Transmission - If you go 727, the shift linkage you have will work, but the slant 6 kickdown will not. You have lots of options for kickdown including Lokar cables or even using easy to find 318 2bbl kickdown (yes, it will work with a 4bbl pretty easy). Keep in mind, if you go with the 727, you'll need a different drive shaft as the 727 is longer. You will also need a 727 torque converter. IF you used a V8 904, it would be a direct bolt in.
  • other things to consider - radiator and exhaust?. Side note, the wiring harness and throttle cable will work from the slant to the V8.
Click to expand...

Thank you for the information!

I’ll be looking at the motor today, and I think the guy also has a good 727 as well. I’ll check out Lokar while I’m at it! Alternatively, would the 904 have to be a v8 transmission, exclusively? I didn’t figure the slant 904 would bolt up, is there any way that’s possible?
 
Ratty73Duster said:
Thank you for the information!

I’ll be looking at the motor today, and I think the guy also has a good 727 as well. I’ll check out Lokar while I’m at it! Alternatively, would the 904 have to be a v8 transmission, exclusively? I didn’t figure the slant 904 would bolt up, is there any way that’s possible?
Click to expand...
slant 6 tranny won't work. You'd need a small block 727 or a V8 904
 
318willrun said:
slant 6 tranny won't work. You'd need a small block 727 or a V8 904
Click to expand...

Ah, okay. In that case, I’ll just go the 727 route! As far as the exhaust goes, I’d like to find a nice set of headers, maybe some kind of cool side-exit exhaust, I dunno.

Surely mounting an aftermarket aluminum rad wouldn’t be too hard?
 
Ratty73Duster said:
Ah, okay. In that case, I’ll just go the 727 route! As far as the exhaust goes, I’d like to find a nice set of headers, maybe some kind of cool side-exit exhaust, I dunno.

Surely mounting an aftermarket aluminum rad wouldn’t be too hard?
Click to expand...
I've ran, and I'm currently running Champion aluminum radiators. Cheap, Chinese from ebay usually 180 bucks to the door. Fit good, maybe just oval a hole or two. Never had them leak, and they cool well. As far as headers, there is a big price range. Ebay/Summit is full of cheapies, and then you can spend more towards Dougs/TTI's. Bare, painted black, or ceramic coated will also influence the price. I personally like Dougs for fitment.
 
My 7.25 rear end is still alive and well in my '74 with the low dollar 318.... And I've beat the skunk out of it over the last 4 years. In fact, I've never broke a 7.25 as long as you only give it 14 second type of power, and that's all I've ever given them.
 
318willrun said:
My 7.25 rear end is still alive and well in my '74 with the low dollar 318.... And I've beat the skunk out of it over the last 4 years. In fact, I've never broke a 7.25 as long as you only give it 14 second type of power, and that's all I've ever given them.
Click to expand...
"results may vary" ~~ :popcorn:
 
318willrun said:
I've ran, and I'm currently running Champion aluminum radiators. Cheap, Chinese from ebay usually 180 bucks to the door. Fit good, maybe just oval a hole or two. Never had them leak, and they cool well. As far as headers, there is a big price range. Ebay/Summit is full of cheapies, and then you can spend more towards Dougs/TTI's. Bare, painted black, or ceramic coated will also influence the price. I personally like Dougs for fitment.
Click to expand...

I checked out the Dougs headers, think I’ll shoot for those. Thank you for the info! It’s about time I got to work on this car, been putting it off for too long!
 
70s Mustang shifter might work. Used one on a 4sp-->727 swap in a TA Challenger. Had to tweek the shifter rod some. Kick down was from another junkyard Challenger.
 
CTC auto ranch doesn't have the correct year you need. Try DVAP Desert Valley Auto parts or AMS obslete. I found a V8 K frame in Texas off of Ebay. I'm doing the same as you. I have a 75 Duster with a cobbled together /6 k frame with a 318 engine
 
Dumb question, but on my Schumacher 318 mounts, will these only fit a LA318, or will a later year 318 fit this configuration? I'm having trouble finding a decent LA 318 Long block.
 
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