Need Info on slant 6 to V8 swap

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johnmucci

johnmucci

moparmucci
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Hi, I just picked up another 66 dodge dart gt. this one had a slant 6 w/ power steering. I have a 273 hi po I want to put in. Here are my questions:

1. Do I have to change the K member? I hear you can buy a motor mount kit from Schumacher instead?

2. Do I need to change the torsion bars?

3. It has 9" brakes, what do I need to change to 10" drum?

4. Is the steering box the same as a V8, I want to send it to Steer & Gear to have it rebuilt cuz I found a floor shift column and want to make it auto/floor

5. Do I need to find a V8 PS Pump or will the 6cyl work?

Heck, that enough for now.. if anyone can assist me that would be great! Thanks for your time
 
HI, and congrats!
I recently did the same thing on my '64 so I may be able to help a bit.

your questions in order:
Q) 1. Do I have to change the K member? I hear you can buy a motor mount kit from Schumacher instead?
A) the K member on all early Darts and Valiants are the same /6 or V-8, you will need V-8 motor mounts, the stock ones are fine, I had to do a little work since I went with a later model 318 and somewhere in the '70's they changed the tabs on the block. you will need mounts from 1964 through 1966.
Q) 2. Do I need to change the torsion bars?
A) no, the /6 is pretty heavy, mine sits the same with the V-8 as it did with the 6. if you want to improve handling you can change the torsions but in general the stock ones should be fine.
Q) 3. It has 9" brakes, what do I need to change to 10" drum?
A) to change to 10" brakes you will need the drums and backing plates and everything between (shoes springs wheel cyls. etc.) this goes for front and rears. I went to the larger bolt pattern and disc brakes off a 1973 Duster to do that requires a little more stuff, if you want I'll give you a list of all the parts you'll need.
Q) 4. Is the steering box the same as a V8, I want to send it to Steer & Gear to have it rebuilt cuz I found a floor shift column and want to make it auto/floor
A) the steering boxes are the same, there are power units and non power. some headders will not allow for power steering, make sure you decide before you commit. there is usually nothing wrong with steering boxes, my advice, if it ain't broke don't fix it. inspect it, clean it up and put it back.
Q) 5. Do I need to find a V8 PS Pump or will the 6cyl work?
A) yes you will need a V-8 pump, you will need to make sure it is compatible with your setup. if you go with the old style cast iron water pump get a pump and brackets compatible with that year. I went with the aluminum pump so I had to have a newer style pump and brackets. also test fit the hoses to make sure you have what you need there are several ends on the high power hose based on the year. both ends vary, make sure your hose fits the box and the pump. the fitting on top of the box is changeable, but don't take out the two bolts, just the fitting on top.

here is the link to my post, you might enjoy reading it:
http://www.forabodiesonly.com/mopar/showthread.php?t=71831
 
37fleetwood pretty much answered all your questions but I would add a couple of things to the answer to question # 4. The V8 power steering gear is the same as the 6 but there is a special 90 degree fitting needed for a V8 setup for clearence under the stock exhaust manifold. On the manual box, most 6cyl's used bushings on the pitman shaft where the V8 box used needle bearings. The needle bearing design is considered stronger but both should work fine.
On question #5, your pump should be the same as the V8. It's the pulley and brackets that are different. If you're not interested in making the car look dead stock, use a complete '67-9 small block setup with the saginaw pump. It's easier to find and has fewer leak problems.
Thanks, Mark
 
I've looked into converting my /6 for years. General consensus is that there's a small enough weight difference between the small block 8 and the completely over engineered /6 to where torsion bars and brakes should be fine. It comes down to the handling, if you're looking to go through the twisty bits a bit quicker then you can now, you're going to need a stiffer front and some bigger brakes.
 
I agree with the above posts, everything pretty much summed up.

I also agree the 9" brakes will be fine unless you plan on racing it, the 64 and early 65 all had 9" brakes and they work fine.
 
My 65 Came with the Commando engine, Suspension package and 9 inch brakes. That is the way they came back then. If keeping it stock on the brakes just drive accordingly .
 
One thing, you will have to get a V8 drag link. The /6 version will not clear the V8's oil pan.
 
WOW! I can't believe I forgot about the drag link, the V* link is dropped about 2" to clear the oil pan.

You can use the /6 link but you need to raise the engine about 1/2", I've done it before and just used a two 1/4" spacers, one on top and one below the mount.
 
thanks for adding the few extra things I forgot to mention. my power steering hose has a tight 90degree bend right after the fitting so I didn't need the brass 90 fitting that came stock, in fact it would have been difficult to use. I also didn't do anything with the drag link, I used a stock 273 pan and it fits tight but doesn't rub or touch steering lock to lock so I left it. if in future I have to do something with the pitman or idler arms I may change it while it is apart. my /6 pump wouldn't fit the stock V-8 pump brackets the clocking of the holes on the back of the can wouldn't allow the bracket to fit. check this before you spend on the pump, you could always make custom brackets, I used all factory stuff so I changed the pump. I'll post a photo or two of my setup.
another thing to quickly mention, you will need matching pulleys for your water pump. because of the difference in depth between the aluminum and cast pump the pulleys from a 318 will not fit your 273 and vise versa. the brackets on your alternator will have the same issue, you won't be able to use 318 brackets with the 273 stuff or 273 brackets with a 318 setup.
the major benefit of using a 318 aluminum water pump is that the outlet is on the same side as your /6 radiator, if you use the 273 cast pump you will need a different radiator. easiest is to rob everything off a newer 318 doner car, still bunches of them show up in junk yards out here.
 
If you decide to switch to 10" brakes in front you will also need a set of spindles for them. The 9" & 10" spindles are different.
 
37fleetwood said:
thanks for adding the few extra things I forgot to mention. my power steering hose has a tight 90degree bend right after the fitting so I didn't need the brass 90 fitting that came stock, in fact it would have been difficult to use. I also didn't do anything with the drag link, I used a stock 273 pan and it fits tight but doesn't rub or touch steering lock to lock so I left it. if in future I have to do something with the pitman or idler arms I may change it while it is apart. my /6 pump wouldn't fit the stock V-8 pump brackets the clocking of the holes on the back of the can wouldn't allow the bracket to fit. check this before you spend on the pump, you could always make custom brackets, I used all factory stuff so I changed the pump. I'll post a photo or two of my setup.
another thing to quickly mention, you will need matching pulleys for your water pump. because of the difference in depth between the aluminum and cast pump the pulleys from a 318 will not fit your 273 and vise versa. the brackets on your alternator will have the same issue, you won't be able to use 318 brackets with the 273 stuff or 273 brackets with a 318 setup.
the major benefit of using a 318 aluminum water pump is that the outlet is on the same side as your /6 radiator, if you use the 273 cast pump you will need a different radiator. easiest is to rob everything off a newer 318 doner car, still bunches of them show up in junk yards out here.
Click to expand...
The '67-9 small blocks (273, 318, 340) without A/C all used the same pulleys and brackets on cars with the same options. Just use them as a set....you can't mix and match with '66 and earlier or '70 and later. There are many A/C setups but there again, whichever year you use, get all the brackets and pulleys off the same engine so everything will line up. The advantage of the '67-9 is that they are fairly easy to find and you can get the Saginaw pump those years and use the smaller diameter return hose. The '66 and earlier are all Federal pumps with the hard to find large return hose. If you run across a complete '70-up setup, by all means go ahead and use it but keep in mind the it makes it a bit harder to see the timing marks unless you redegree your balancer and pointer to the other side. You'll have to redesign your raditator no matter which setup you use. The factory /6 had a curved lower hose connection so none of the stock V8 lower hoses will fit right anyway. Just have your radiator guy pull the tanks, rod and repair as necessary, and install the correct hose nipple where ever you need it to use a stock hose.
Thanks, Mark
 
cudamark said:
The '67-9 small blocks (273, 318, 340) without A/C all used the same pulleys and brackets on cars with the same options. Just use them as a set....you can't mix and match with '66 and earlier or '70 and later. There are many A/C setups but there again, whichever year you use, get all the brackets and pulleys off the same engine so everything will line up. The advantage of the '67-9 is that they are fairly easy to find and you can get the Saginaw pump those years and use the smaller diameter return hose. The '66 and earlier are all Federal pumps with the hard to find large return hose. If you run across a complete '70-up setup, by all means go ahead and use it but keep in mind the it makes it a bit harder to see the timing marks unless you re-degree your balancer and pointer to the other side. You'll have to redesign your radiator no matter which setup you use. The factory /6 had a curved lower hose connection so none of the stock V8 lower hoses will fit right anyway. Just have your radiator guy pull the tanks, rod and repair as necessary, and install the correct hose nipple where ever you need it to use a stock hose.
Thanks, Mark
Click to expand...
I used the front cover and damper off the 318 so it all matches, again whatever way you go get all of it.
I used the /6 radiator with no alterations, I simply got a hose that bent the way I needed, it works fine, another thing to remember is that the outlet on the /6 is smaller than on the V-8, you either have to find a hose with both sizes of ends or use the hose clamp to pull the size down, use your judgment, what I did may not be for everyone but it was the cheapest way.
 
If it still runs; leave the /6 in there and Drive it. :)

The gas mileage is pretty good,
and the slant 6 is no slouch. :)
 
I Just picked u a 66 Dart GT /6 that i would like to up grade to a v8 , I read ALL chat great info. what would be the best power plant to use 340 ? will my slant 6 trans fit any small block V8 trans plant. This Dart GT was purchased from the orgional owner with 35k miles on it .
Thankd
davidd
 
:happy10::happy10:
davidd said:
I Just picked u a 66 Dart GT /6 that i would like to up grade to a v8 , I read ALL chat great info. what would be the best power plant to use 340 ? will my slant 6 trans fit any small block V8 trans plant. This Dart GT was purchased from the orgional owner with 35k miles on it .
Thankd
davidd
Click to expand...
 
davidd said:
I Just picked u a 66 Dart GT /6 that i would like to up grade to a v8 , I read ALL chat great info. what would be the best power plant to use 340 ? will my slant 6 trans fit any small block V8 trans plant. This Dart GT was purchased from the orgional owner with 35k miles on it .
Thankd
davidd
Click to expand...

340's are expensive...get a 360...cheap and plentiful, and 20 extra cubes dont hurt either.

V8 will not bolt to /6 trans. You need a V8 trans case. The internals are mostly the same as /6 trans,though.

'66 seems to be a change-over year...some slants came w /dropped centerlink, some didn't.

Hope this helps...
 
johnmucci said:
Hi, I just picked up another 66 dodge dart gt. this one had a slant 6 w/ power steering. I have a 273 hi po I want to put in. Here are my questions:

1. Do I have to change the K member? I hear you can buy a motor mount kit from Schumacher instead?
Click to expand...
No. Use stock mounts up to 1972. The 73+ mounts are not compatible with the earlier k-frames

johnmucci said:
2. Do I need to change the torsion bars?
Click to expand...
If the /6 is a 225, maybe. If the /6 is a 170, definitely. The 225 with A/C used the same bars as the V8 w/o A/C. The engine weight is only about 50 lbs different. The 170 used a shorter block that is noticably lighter than the 225.

johnmucci said:
3. It has 9" brakes, what do I need to change to 10" drum?
Click to expand...
Need to swap spindles. FWIW: In the course of studying for the resto of my first 66, I read that all '66 V8s had 10" drums as standard equipment. I'm a big fan of being able to stop on cue. The cheapest upgrade I can think of is to use the 9" drums from a 71 or 72. These radially drums were heavier which translates into being able to take a bit more abuse before fading. As I recall the 66 brake drums were finned around the circumference.

johnmucci said:
4. Is the steering box the same as a V8, I want to send it to Steer & Gear to have it rebuilt cuz I found a floor shift column and want to make it auto/floor
Click to expand...
Yes. You will need the dropped center link.

johnmucci said:
5. Do I need to find a V8 PS Pump or will the 6cyl work?
Click to expand...
The pump will work. The issue will be how to mount it. You'll need the V8 mounting brackets for your pump.

Good luck with the HiPo 273. It's a little soft on the low end, but it does nicely when wound up. I had the factory single exhaust on my HiPo car. Still miss the sound. It's that good.
 
The 65 10's and the 66's were different? I got some 10's on the floor right now and they are not finned. As far as I know they are stock "S" brakes. The 9-10 spindle is different but I dont know how, The Scarebird disk conversion calls out 9 inch spindles. The original 65 mounts are thick rubber,like 3 inches on the original brackets. The newer biscuit mounts are much thinner, like 1.25" total. Dont know if the brackets changed to a shorter one in the 67 or what, but the motor might sit lower with the post 66 mount setup.
 
the 10" spindles are heavier than the 9" spindles which are kind of flimsy in comparison
scarebird makes an inexpensive disk brake conversion (using GM parts) for 10" spindles, and one for 9" spindles
http://www.scarebird.com/
 
pishta said:
The 65 10's and the 66's were different? I got some 10's on the floor right now and they are not finned. As far as I know they are stock "S" brakes. The 9-10 spindle is different but I dont know how, The Scarebird disk conversion calls out 9 inch spindles. The original 65 mounts are thick rubber,like 3 inches on the original brackets. The newer biscuit mounts are much thinner, like 1.25" total. Dont know if the brackets changed to a shorter one in the 67 or what, but the motor might sit lower with the post 66 mount setup.
Click to expand...
All the '65-72 A-bodies with 10" drum brakes had smooth drums. '73-6 used finned ones. The 9" brakes started the fins in 1970. I wouldn't use the 9" brakes or spindles for any kind of brake system. The bearing sizes are way too small and don't hold up to any heavy duty performance use.
 
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