Technical Dodge slant 6 - super 6 conversion

Hey fellas. I have an old Dodge Dart with a slant 6, pulled the old tired slant to replace with a rebuilt, earlier slant 6 that has some hot rod stuff in it that I got from a fellow HAMBer. It came with a partial Super Six setup. I got the two-barrel manifold and the kickdown bracket. I did not get the kickdown rod itself.



I don't want to do a cable, they're pretty ugly and expensive, but apparently a used 2-bbl kickdown rod is like $400 on ebay... can I not just hack up the 1bbl linkage? Cut & weld some length into it, bend it up...? I don't have the engine in the car yet as I'm waiting on a torque converter so just looking for ideas... couple people have told me it can't be done but I don't see why not?? Hoping someone's got some experience to share.

 

Hard to imagine it can't be done. Some pictures of what your trying to pull off would help.

 

You can cut and weld the old kick down link to work , I've done it many times , but the Lokar cable set up works pretty slick .

 

It's hard to photograph when it's all together and harder still since the engine isn't in the car yet and I don't have the part I'm trying to make haha. Just hoping someone has some experience with these engines and knows what I'm talking about.

I'm counting on being able to cut and weld it right now. You're the first person that's said he's done it and I've asked in several slant 6 specific groups... got a bunch of shrugs and a few guys saying it was impossible.

 

I've never seen the kickdown linkage layout on a slant Super Six. But I can't imagine it being a particularly complicated affair.

I think there's mainly one goal to keep in mind when trying to fabricate the linkage rod. When it's all said and done you want to make sure that at wide open throttle, the rod moves the t/v lever on the trans as far back as it can go. If the rod attaches to the 2 bbl carb using a similar slotted, threaded adjuster like most old Torqueflites used it should simplify making this final adjustment.

The adjustment at idle and part throttle opening are much less critical.

 

What @ClayMart said. This is the important part.

"I think there's mainly one goal to keep in mind when trying to fabricate the linkage rod. When it's all said and done you want to make sure that at wide open throttle, the rod moves the t/v lever on the trans as far back as it can go. If the rod attaches to the 2 bbl carb using a similar slotted, threaded adjuster like most old Torqueflites used it should simplify making this final adjustment."

Dave

 

The reason most Mopar guys are shrugging is because most haven't built a slant 6, and those that have probably just used the parts from the Super 6 donor.

I have no idea what that super six kickdown rod looks like, but I'd bet it wouldn't be hard to figure out.
The reality is, it needs to miss everything as it moves forward and back. It has to work with the throttle linkage, and move the lever on the transmission in the correct direction. And it has to be able to be correctly adjusted.

Just like any other fabrication project. Its going to take longer to make it look pretty then it will to make it function.

 

Back in the late 60's here in Australia the Slant Six got up graded for the Valiant with the addition of a 2 barrel carb which upped the HP from 145 to 160 and the cars had 160HP badges on them. Was not called Super Six. I have a mate who was a Chrysler dealer at that time and he may have manuals with the info you need. I can ask him if you want. I actually have a manifold and carb off a 160HP engine.

 

I recall seeing an aluminum intake manifold on a slant six that a friend scrapped years ago, is that part of the "Super Six" package?

I can only imagine the congestion on the right side of the engine bay of a slant six on an Australian RHD car.

 

I will ask my buddy... He lives this stuff!!

 

There are 1 barrel aluminum factory intakes. My brother R.I.P. cut the plenum open on one and welded an aluminum plate he drilled for a 4 barrel carb. I still have it 40 plus years later.

The pic above looks like maybe a Hyper Pac factory 4 barrel and exhaust. Looks like it is a Valiant or Lancer. They were screamers!

His/my '62 Lancer that had the hot slant 6 got a 340 many years ago after the slant 6 got tired.

Dave

 

The linkage to the transmission is actually the throttle pressure control linkage. Do not operate the vehicle without the linkage connected and properly adjusted. It controls the operating pressure of the transmission. Without it being connected the transmission will always operate at minimum pressures and the transmission will slip under hard throttle.

I worked at a Dodge dealership for a number of years and I believe the linkage would be easy to fabricate. The linkage was very similar on the V8's and the 6's.

 

Appreciate it guys! Nobody has said "I tried it myself and here's why it didn't work" so I'm pretty confident I can do it just the way I had planned.

The way this motor was built, I think it would probably like a 4 barrel... but that's in the distant future... what I've got should be leaps and bounds better than the motor it's replacing... which was a tired, 300,000+ mile 1 barrel mill. That old motor still runs - even though you can turn it over with the plugs in it with one hand on the crank pulley - so I'm planning to give it a well-deserved refresh and maybe use it in my next cheap-ass hot rod build?

 

You can do it.
I MIGHT be able to take a couple pictures for you, but it's a busy day today.
As said, you gotta get this right or the trans is going to be short-lived. Is the trans the one that was behind the 300K engine all that time?
You mention early rebuilt engine. The Super six is later, but should bolt up. Hope they decked the block, that's a big factor in getting more HP. Early also means solid lifters and adjustable rockers. Proper break-in!
I have cautioned others before to make sure the 2 manifolds are fitted carefully with flat mating surfaces and new or good shape bolts and quality gaskets, properly torqued.

 

Pretty thorough description of making the Super Six conversion at the link below, if you've not seen it already. There's some decent pictures of parts and the overall layout of things, and a lot of helpful general advice.

https://www.slantsix.org/articles/supersix/article.htm

The kickdown linkage does look a bit more convoluted that what I'd imagined. It still doesn't look to be insurmountable though.

 

Okay, this was a 3.5 hands needed task in a dark cold corner of the garage, so these are not the best.
First, the linkage at the trans with a tape measure, throttle closed.

Next, just closed.
now with the linkage fully pushed back

It looked like just about 2 inches, you can check yours.
Note that the spring down here is not compressed. When the adjustment pinch bolt is tight, the linkage and pivot are locked. The spring is used during adjustment only.

 

Here's an article (sales pitch) on these
https://www.motortrend.com/how-to/the-lowdown-on-stock-torqueflite-kick-down-linkage/
Now the linkage at the carb. I just moved the 'kickdown' , not the throttle because of the access where this is sitting. measuring tape in view, also there is a pivot at bottom right. This is at rest throttle closed, trans linkage forward with spring pressure.

Now, at rest.

Now with the kickdown pulled back (not the throttle, sorry).

 

I would have done a better job documenting this, but it is buried and as the article shows, there are a BUNCH of different parts and the best way to go is grab a complete setup (or buy the aftermarket).
I will be away from the computer for a while, but if you decide to try to craft your own and need more info, ask away. I'll check back later.

 

It is actually a 1985 block & head with hydraulic lifters, a Hughes cam, 2bbl manifold and an early forged crank that was built to go in an early A-body. I will be running a 6-into-1 long tube header on it and using a Remflex gasket to make sure everything seals up good.

I am bolting it to the old transmission but it was rebuilt a couple years ago and is in great shape…

Thanks for the pics and measurements Rod- they’ll be really helpful. I’ll holler at you if I need anything else. I know getting pics of this stuff is really a pain.

 

If that old transmission was older then 1968 (I believe that was the change over year), there could be a problem with the hub on the torque converter, the newer converter hubs have a smaller diameter and the old converter design won't work (you couldn't just swap out the converters at that time). My BIL had a 63 Valent slant 6 and we tried to swap in a 1970 slant 6 and the converter hub wouldn't let the trans bolt up tight to the motor. I can't remember for sure, but I believe we ended up using the 70 transmission as well.

 

Yep!… wish someone had told me that last week! I had the local transmission shop build me a torque converter.

The way it goes is, if you have a late crankshaft and an early transmission, you can use any 904 torque converter but there is an adapter bushing that fits between the torque converter pilot & the pocket on the crank.

If, like me, you have an early crank and a late transmission, you’re just hosed unless you have a torque converter modified or replace the input shaft & pump in the transmission with that from an early transmission.

 

Man this brings back some memories! I was a die hard Mopar fan at one time and built one heck of a slant 6 for an OT Duster. I did a lot of head work, used an Offy 4bl intake, Purple Shaft cam, bored it out and bumped up the compression, and ran a set of Clifford split headers through full exhaust with a 3 speed stick on the floor. I’d pull up at the local cruise ins and people thought I had a mild 318 in it. That was the most fun car I had built because when I popped the hood their mouths would drop.
Even though I am a flathead guy I still love the 6 cyl just because they are cool in my book

 

Hmmm, I put a Slant six from a 79 Aspen in my 65 Coronet years ago. I wonder if I should have had a bushing as you say...... I sold it years ago and guess it is still running??

 

Honestly I think the flex plate is doing most of the work - I don’t know how important that adapter really is, but the slant guys mentioned it… I would guess that extremely spirited driving may stress the input shaft a little more with the torque converter pilot unsupported in the crank.

 

I have seen several flex plates break running early trans on a late engine. Not a good idea.

Dave

 

Its possible the 65 had a newer trans in it, or its possible I had the wrong year of change over. My experience was with a 63 transmission and a 71 or 72 motor.

The hub on the old trans torque converter would make contact with the newer motor's crankshaft and you couldn't get the transmission any closer then a 1/2" away from bolting to the motor.

 

Forgot to come back and mention I got the thing going. I tried a few approaches for making up a rod to work, but I couldn't come up with something that would work around my 6-into-1 long tube header... that thing eats up a lot of space in the engine compartment. Ended up finding a slick way to run a cable, just had to fabricate a simple plate for the throttle linkage. I'll take a picture showing the way I did it tomorrow if I think about it.

 

Good to hear, hope you put in a good starter. Stock they are easy to swap, sounds like that's no longer the case, plus heat.
I enjoy being different, and am a Mopar guy. The /6 is a neat engine, but to really shine, it must either be a low revving workhorse or a bit of a limited (pushrod, non cross flow) zinger in a super light car.
Considering all the stuff built since then that are higher output, lighter and smaller, it's hard for me to get excited, but I understand the fervor the people have.

 

The Mopar guys who shrug their shoulders and say it's impossible are the same ones trying to sell them for an astronomical price. Mopar guys think that shit is worth its weight in gold. Here, HAMB cats build &craft the pieces required and will offer support , advice and encouragement for you to do the same . Remember the fundamentals!

 

Here’s roadster that showed up at a local Cruz in last Friday. Running the Super Six setup with a small turbo. Also interesting is he was running a SlantSix 727 which are hard to find.