Engine Swapping the Slant 6

[66FURY_III]

Hello everyone,

As the title suggests I'm about to start the process of swapping the engine in my 66 Fury III and have a line on a 400 big block with a 727 transmission for a decent price.

I just wanted to get all the parts sorted as best as possible before I yank the engine out and from what I've read the motor mounts are the hardest thing to get.


For reference its a 1966 Plymouth Fury III with manual brakes, 8 3/4 rear end and a leaky slant 6.

I know that there are many people that love the slant and I understand however I want that lumpy low growl from a V8 and the ability to roast the tires.

The slant has served me well and will be built up at some point as a fun engine to possibly swap into a roller down the road.

For the time being just treat me as a complete beginner in this whole process, I'm going way out of my wheelhouse to try out an engine swap.

If anyone here has done a slant 6 to Big block conversion at all I'm all ears.

View attachment 591339

 

[volksworld]

maybe i'm crazy but i always thought the subframe needed to be changed as the 6 cyl mounting points were in the wrong spots

 

[cbarge]

maybe i'm crazy but i always thought the subframe needed to be changed as the 6 cyl mounting points were in the wrong spots

Schumacher used to make conversion motor mounts from slant six to V8.
But they had not hsve any in a long time.

Keep in mind upgrading to a big block you will need to upgrade the tirsion bars and rear springs .
The slant six torsion bars are fine for drag racing but as a driver, the added weight and HP will need V8 bars.
Rear springs will need to handle the upgrade in torque.
See?
It can turn into a snowball in a hurry.

Slanty powered C's were the norm in Canada in the 60's.
Not many examples are left.

 

[Triple Pickle]

Stock 400s are not known for their performance. They were a smog era engine. Low compression and terrible mileage.
As far as sound, look at the price of B-block headers for a C-body. You’ll need them if you want to wake up that 400 with a performance build.
A LA engine might be a better choice.
V8 swaps include radiator, driveshaft, torsion bars, exhaust, and if you haven’t upgraded the brakes, you’ll need to do so if you’re planning on some high spirited driving. Along with the stub frame mentioned above,

 

[cbarge]

So you have a 400 and 727...why not get another C roller that donated its vital organs?
Any big block C will have the V8 goodies already in place..
just drop yer 400 in...
Plenty out there
As I mentioned, Canadian built 66 Fury's with the slanty is a rare bird nowadays.
I bet it makes a good conversation piece.
There is an underground following of the slanty and there are cheap mods to get more power out of it.
Something to ponder..lol

 

[gyknot]

The Schumaker mounts were made to put the big block into an A body car. When I bought a set years ago, I asked them if they would work on any slant 6 conversion. The answer I got was they didn't know. I figured it was worth the chance.
I bought a set anyways and have never used them. At this point I never will as I've decided to keep mine a slant 6 now.
They are available if you want them. Just PM me.

 

[commando1]

I had a '66 Fury /6 that I dropped a 440 into.
No, there are no conversion kits to put a BB into a /6 C-body stub frame.
Lots of DIY fabrication required.
How's your welding skills?
I recommend you put in a SB.

 

[66FURY_III]

Wow thank you everyone!
I appreciate the insight into this all, gives me a lot to think about for sure.

@commando1
My welding skills are slightly better than Stevie wonder….only just.


I think that based on what everyone is saying, coupled with the cost of big block parts, I’ll pursue the small block. I know of a 318 and 727 from a dodge diplomat but that will be full lean burn for sure.

@gyknot thank you for that, let me do some research on the measurements and I’ll reach out to you.


I know I want to swap out the brakes in the front for sure, the single master cylinder always has me worried.
The suspension is pretty tired so it would need to be changed anyhow so it makes sense to upgrade it to handle the extra weight etc.

I really appreciate the support on this forum, the knowledge here is amazing. If anyone has any tips or tricks doing this type of swap that hasn’t been mentioned please feel free to add it.

I’ll keep everyone posted as I start this journey.

 

[Mr onetwo]

a roller magnum 360 is the best way to go....literally thousands out there. B/RB engines are big, heavy and run hot.Parts are expensive.Sell that 400 to someone who is going to bore and stroke it to create a monster...small block all the way

 

[cbarge]

a roller magnum 360 is the best way to go....literally thousands out there. B/RB engines are big, heavy and run hot.Parts are expensive.Sell that 400 to someone who is going to bore and stroke it to create a monster...small block all the way

I tend to agree. A well built 360 can make just as much or more good horsepower and torque than a stock 383

 

[66FURY_III]

a roller magnum 360 is the best way to go....literally thousands out there. B/RB engines are big, heavy and run hot.Parts are expensive.Sell that 400 to someone who is going to bore and stroke it to create a monster...small block all the way

Alright sounds good to me. I’ll start the junk yard hunt this week and see what I can find. I know the yard down the street has a bunch of options, they’re the ones with the mid 80s 318.

Any specific year of 360 magnum I should be looking out for? These were in the pickups and Dakotas so I’m sure they have a few, I’ll start calling around.
If they only have fuel injected 5.9s is it terribly difficult to convert back to carbureted? I do like the part’s availability though

 

[Mr onetwo]

If it were me I would find a 1992 to 2004 magnum roller block and depending on budget either EQ iron heads or Eddy aluminum heads.
Chrysler Dodge Magnum 318 / 360 1992 - 2004 Cylinder Heads, Assembled (Pair) - EQ Cores & Recycling
2002 DODGE RAM 1500 Edelbrock 61775 Edelbrock Performer RPM Chrysler Magnum Cylinder Heads | Summit Racing

Engine mounts and an intake will have to be addressed.Keep in mind the balancing difference between 318 and 360 engines...make sure everything matches whether auto or manual transmission.

 

[66FURY_III]

Just wanted to update everyone, I wanted to get a 360 magnum engine however our local wreckers do not have engines that were complete (I live in a farming community so these have been picked over to keep the farm trucks running) and the rest of the dodges in the yard were hemis or missing engines completely. As cool as it would be to have a hemi, headers and heads were way out of the budget for what I'm doing with a driver quality car.

So that being said I have a 318 with a 727 trans being delivered within the next few weeks depending on scheduling and I'll start the process of converting the lean burn to an old ignition system. Keep in mind I've got no experience so it will be a learning process for me but to quote the great Jim Lahey from Trailer park boys "I'm sober enough to know what I'm doing, and drunk enough to really enjoy it."

I'll update as I go about this process.

As it stands now I'm looking for any slant 6 to small block Schumaker mounts. I know @gyknot had some slant to big block ones.

In the meantime I'm upgrading the suspension to take the added weight as pointed out by everyone so far. Also just replacing all the worn out bushings etc. Should make it feel less sketchy

 

[cbarge]

Just wanted to update everyone, I wanted to get a 360 magnum engine however our local wreckers do not have engines that were complete (I live in a farming community so these have been picked over to keep the farm trucks running) and the rest of the dodges in the yard were hemis or missing engines completely. As cool as it would be to have a hemi, headers and heads were way out of the budget for what I'm doing with a driver quality car.

So that being said I have a 318 with a 727 trans being delivered within the next few weeks depending on scheduling and I'll start the process of converting the lean burn to an old ignition system. Keep in mind I've got no experience so it will be a learning process for me but to quote the great Jim Lahey from Trailer park boys "I'm sober enough to know what I'm doing, and drunk enough to really enjoy it."

I'll update as I go about this process.

As it stands now I'm looking for any slant 6 to small block Schumaker mounts. I know @gyknot had some slant to big block ones.

In the meantime I'm upgrading the suspension to take the added weight as pointed out by everyone so far. Also just replacing all the worn out bushings etc. Should make it feel less sketchy

At this point, with worn suspension parts on a /6 stub frame, it is best to search a V8 stub frame and rebuild the suspension on it prior to installing under the car.
Most V8 stubs have sway bars.
V8 torsion bars will be a plus.
Just my opinion.

 

[Big_John]

IMHO, it will be a zillion times easier to replace the stub frame with a V8 version.

Since this is your first engine swap, it's much better to do bolt on stuff versus having to weld up new mounts.

My welding skills are slightly better than Stevie wonder….only just.

Besides welding the mounts, you have to position the motor correctly. That means fore and aft, up and down, and side to side. You'll have to figure out the radiator inlet/outlets and hoses. That might mean changing the water pump housing and/or radiator. Then there's the throttle linkage and the driveshaft. So much stuff is different from the slant to the 318....

Then there's this....

I want that lumpy low growl from a V8 and the ability to roast the tires.

That smog version of a 318 ain't gonna do it... In fact, tuned right, the slant would probably pull as hard as the junkyard 318. That is if that 318 was worth bringing home... Remember they are in a junkyard for a reason.

So if you want to do this, great... Just save yourself hours of frustration by using factory parts like the V8 stub frame.

 

[Mr onetwo]

find 302 heads

 

[Triple Pickle]

Whichever route you choose be aware that it’s going to be much more expensive than you think. Unless you acquire a donor car that has all the parts you need you’ll be scrounging for every little piece and paying a premium price for each one.
As mentioned above most junkyard engines are lucky to be a good core. Nothing worse than going through all that work to find out you got a smoking dog of an engine.
I always check the bore and rotating assembly on a mystery engine. Rarely have I found one that doesn’t need something. Not trying to discourage you. Just saying it WILL be expensive!

 

[66FURY_III]

I appreciate all the input and support from everyone. I have no doubt it will be more money than I'd like it to be but at this point I'm looking forward to working on the car again, that has been missing for a few years.

I'm lucky to have a local mechanic who's an old school racer and builds on his days off. That coupled with a few wreckers that are very willing to help out with parts at reasonable prices, I'm happy to give it a good shot.

I've called Mopar National Parts and he's off to get a Stub frame and related parts set aside for me. Great guy

I'm very much looking forward to learning something new

 

[66FURY_III]

I just wanted to give an update on this project.

I have purchased a 318 with a 904 from a 1985 Fifth Ave, this car was driven to the spot where it rested until I found it. The engine is now in my garage on a stand, torn down and I am just waiting on some seals for the valve covers. The engine was coated in thick oil mixed with dirt that all comes from those rock hard valve cover gaskets.

I also learned that the car belonged to a local famer who lived on a dirt road so it makes sense why it was so nasty.

The valve train looks pretty clean and when I pulled the plugs I found them to be in really good shape, no oil and just some very light carbon.

I'm having a good time tinkering around in the garage during our winter months.

I'm still looking for a set of conversion engine mounts to go from the /6 to v8. That seems to be a the only questionable part I need.

Enjoy your week gents

 

[cbarge]

have purchased a 318 with a 904 from a 1985 Fifth Ave

85 will have the A998 lockup trans with the super low first gear since most M bodies had a 2.2 rear gear ratio.
Not a bad transmission, they are reliable as long as the lock up does not act up.
The engine will have smog heads with small exhaust ports below the normal exhaust ports.
You can either run the 85 manifolds or drill tap and plug the smog ports.
Some mid 80's 318 had additional smog pipes attached to the back of the exhaust manifolds that can be cut and sealed.
Hope this helps.