Will a /6 904 bolt up to a 318?--UPDATE

Posted By: 340727dart

Will a /6 904 bolt up to a 318?--UPDATE - 08/25/08 09:12 PM

The /6 in my '71 Swinger is pathetically slow. It still gets 17 to 18 mpg in town but, dang, it takes forever to get up to speed.
And, it does not like running 70 mph on the Interstate.
So, I figured to locate a 318/2v and swap it into the car.
It would be great if I can use the 904 currently in the car.

Posted By: RapidRobert

Re: Will a /6 904 bolt up to a 318? - 08/25/08 09:39 PM

unfortunately no it wont.

Posted By: RodStRace

Re: Will a /6 904 bolt up to a 318? - 08/25/08 09:43 PM

NO. The 318 will require special mounts or a V8 K member too.
Try really tuning the /6. a '71 should have a solid cam. Run the valves, do a full ignition tune-up and check out the carb. Change the filters. Also make sure the exhaust isn't plugged.
Empty out the interior and trunk of extra junk, get an alignment. Run the tires at 35 PSI.
Have you changed the ATF and rear lube?

Posted By: 340727dart

Re: Will a /6 904 bolt up to a 318? - 08/25/08 09:52 PM

Quote:

NO. The 318 will require special mounts or a V8 K member too.
Try really tuning the /6. a '71 should have a solid cam. Run the valves, do a full ignition tune-up and check out the carb. Change the filters. Also make sure the exhaust isn't plugged.
Empty out the interior and trunk of extra junk, get an alignment. Run the tires at 35 PSI.
Have you changed the ATF and rear lube?

I know about the differences in the K-members and motor mounts.
And, I stay on top of the tune up with the slant. I recently converted to a Pertronix ignition. All the filters are new, I ran the valves about a month ago.
There is nothing in the trunk. I've changed all the fluids within the past month as well.
Let's face it, brand new, the engine put out only 145 gross horsepower.
That means it probably nets about 115 to 120 at the rear wheels.
Given that the engine now has about 94k miles on it, it's probably down to 100 rwhp.
The car probably weighs over 3000 lbs.
That combination, along with 2.94 rear gears, just does not lend itself to fun driving.
And, at times, it gets downright scary when trying to keep up with the flow of traffic.
I figure I can pick up a good, complete, 318 for less than the price of just a Super Six set up and still get decent gas mileage.

Posted By: marklock

Re: Will a /6 904 bolt up to a 318? - 08/25/08 10:05 PM

My 72 Swinger with the slanty ran really well. Again with a good tune up and such it more than got out of its own way on the express way and around town. Maybe it was a freak or something, and no way do I mean it was fast, just a cool around town car.

Posted By: RodStRace

Re: Will a /6 904 bolt up to a 318? - 08/26/08 02:52 AM

Sorry, didn't mean to offend, but straight 6s and slants are known as torque motors and they will rev, so when I hear no low end and no top end, I go to the basics..

The 2.76s might be the real cause. See if you can try 3.23s or 3.55s.

Posted By: FarDarter

Re: Will a /6 904 bolt up to a 318? - 08/26/08 04:00 AM

No, screw that slant six and go with the 318. That's exactly what I'm doing and I'm behind you 100 percent. They may be tough and all that but /6's are dogs. You probably have a decent chance of finding a whole driveline from a V8 car or at least the engine+trans combo. I found a 318 and 904 combo from a running car for $250. Hopefully you can do the same. Good luck!

Posted By: dustpan man

Re: Will a /6 904 bolt up to a 318? - 08/26/08 04:11 AM

y a 318 tho put a 360 in it if u want more but if i was u i would turn timming up a 318 has no more power then a 225 but u do a tune up get different gears like 323s or 355s youl like it trust me u can chrip every gear i did the same save some money and you should be getting 24 to 26 miles to the gal of gas

Posted By: 68Cbarge

Re: Will a /6 904 bolt up to a 318? - 08/26/08 04:23 AM

The slanty can make power and still be a miser.
Check out the Slant Six Forum.
They do have a recipe that can give you power and economy.

http://www.slantsix.org/articles/articles.htm

Between 1978 and 1981,Ma used a 2bbl intake and carb,and 2-1/4" exhaust for more power and torque.Yet it still maintained good fuel economy.
A common swap is to install the Super six gear on an older slanty,recurve the dizzy,install a clutch fan and shroud.
Plus -as mentioned-go with 3.23's in the rear.
It will run forever and make more power than smogged up late model 318 in a 5Th or Dippy.

Posted By: CHRONiklyDEMONic

Re: Will a /6 904 bolt up to a 318? - 08/26/08 07:01 AM

Quote:

slants are known as torque motors

Posted By: MoparforLife

Re: Will a /6 904 bolt up to a 318? - 08/26/08 11:17 AM

Leaning tower of power.

Posted By: scratchnfotraction

Re: Will a /6 904 bolt up to a 318? - 08/26/08 12:30 PM

add a super six intake and 2-v carb

add a high stall tc to it

change the rear gear

the 3 best things I have done for my slants,its the best way to get a stock /6 to run and still be stock

Posted By: 340727dart

Re: Will a /6 904 bolt up to a 318? - 08/26/08 04:08 PM

Quote:

Sorry, didn't mean to offend, but straight 6s and slants are known as torque motors and they will rev, so when I hear no low end and no top end, I go to the basics..

The 2.76s might be the real cause. See if you can try 3.23s or 3.55s.

No worries. I asked for advice. You offered yours. You certainly didn't offend me.

But, I am still looking for a 318/904 combo.

Posted By: slantzilla

Re: Will a /6 904 bolt up to a 318? - 08/26/08 04:55 PM

Mine runs OK.

Posted By: Anonymous

Re: Will a /6 904 bolt up to a 318? - 08/26/08 05:02 PM

Slant 6 is no ball of fire, but it really shouldn't have a problem keeping up with traffic or cruising at 70. 2.94 gears work well with a slant, and 94,000 miles isn't that much, either.

I have to wonder about the condition of your timing chain/gears, or if your muffler is plugged (they CAN corrode internally).

Lots of work/expense to swap in a 318; if you're only looking for a stock 318 power level, you can get that in a slant 6 with a 2bbl carb, mild cam, and bigger exhaust pipe.

Posted By: 340727dart

Re: Will a /6 904 bolt up to a 318? - 08/26/08 06:59 PM

Quote:

Slant 6 is no ball of fire, but it really shouldn't have a problem keeping up with traffic or cruising at 70. 2.94 gears work well with a slant, and 94,000 miles isn't that much, either.

I have to wonder about the condition of your timing chain/gears, or if your muffler is plugged (they CAN corrode internally).

Lots of work/expense to swap in a 318; if you're only looking for a stock 318 power level, you can get that in a slant 6 with a 2bbl carb, mild cam, and bigger exhaust pipe.

How can I check the condition of the muffler? I put my hand over the tail pipe with the engine idling yesterday and it sure seemed like it was moving a good amount of air.
The muffler and tail pipe have been changed at some point in the car's life prior to my owning it.
As far as the 318, I was planning on port matching the heads and intake manifold, along with smoothing (not porting) the intake and exhaust ports, then smoothing the exhaust manifolds as much as possible and going with dual 2 1/4" exhaust.
I've been looking at Super Six parts and they seem to be more expensive than a good used 318.

Posted By: Anonymous

Re: Will a /6 904 bolt up to a 318? - 08/26/08 07:49 PM

Quote:

How can I check the condition of the muffler? I put my hand over the tail pipe with the engine idling yesterday and it sure seemed like it was moving a good amount of air.
The muffler and tail pipe have been changed at some point in the car's life prior to my owning it.

Try holding your hand over the tail pipe while someone in the car revs the engine up. Should get a nice increase in volume if it's not clogged. Of course you could just cut the muffler off and see if it runs any better.

Quote:

As far as the 318, I was planning on port matching the heads and intake manifold, along with smoothing (not porting) the intake and exhaust ports, then smoothing the exhaust manifolds as much as possible and going with dual 2 1/4" exhaust.

Hmmmm, other than dual exhaust, I don't see these mods doing much for an otherwise stock 318.

Quote:

I've been looking at Super Six parts and they seem to be more expensive than a good used 318.

Yeah, costs about as much to hop up a slant 6 as it does a 318, and at the same level of mods, the 318 would make more power. V-8 swap would still be more expensive (and time-consuming) because you'll have issues other than just the engine/tranny - lot of little things, exhaust, radiator, k-frame, center link, throttle and kickdown linkage, etc. etc. And if you upgrade the 318 to make much more power than stock, then you are looking at a rear end swap, plus upgraded suspension/brakes etc.

I converted my 67 Barracuda from Slant 6 to 360, so I'm not wedded to keeping a slant; just want to give you a heads up about what you would be getting into.

Posted By: That AMC Guy

Re: Will a /6 904 bolt up to a 318? - 08/26/08 07:55 PM

I once had a slant 6 with a straight pipe. Never once got pulled over for being too noisy! The exhaust manifold is restriction enough.

Posted By: ZIPPY

Re: Will a /6 904 bolt up to a 318? - 08/26/08 08:48 PM

What you should do is find a rusted or wrecked car (or truck) with a good running 318 and good trans in it, take everything, and put it in your car.

Posted By: RapidRobert

Re: Will a /6 904 bolt up to a 318? - 08/26/08 08:58 PM

Quote:

I once had a slant 6 with a straight pipe. Never once got pulled over for being too noisy!

Me too.

Posted By: MoparJoe

Re: Will a /6 904 bolt up to a 318? - 08/27/08 01:09 AM

"Lots of work/expense to swap in a 318; if you're only looking for a stock 318 power level, you can get that in a slant 6 with a 2bbl carb, mild cam, and bigger exhaust pipe."

Huh?

Even if you do all that stuff you're still missing about 80hp/100 lb/tq compared to a stock 2barrel 318. About the hardest part of doing a /6 to 318 swap is getting the lopsided lump out of the car without trashing the bulkhead connector, after the 1st time you learn to disconnect it and push it inside the car.

On a 67-72 A body a /6/904 to 318/904 swap shouldn't take more than 1 day, if it does you're doing something wrong.

Posted By: Anonymous

Re: Will a /6 904 bolt up to a 318? - 08/27/08 02:08 AM

Quote:

Huh?

Even if you do all that stuff you're still missing about 80hp/100 lb/tq compared to a stock 2barrel 318.

??? Comparing factory net hp ratings, there's only 50 hp difference, stock to stock.

Quote:

On a 67-72 A body a /6/904 to 318/904 swap shouldn't take more than 1 day, if it does you're doing something wrong.

Guess I'm slow then . . .

Posted By: 340727dart

Re: Will a /6 904 bolt up to a 318? - 08/27/08 02:16 AM

Quote:

About the hardest part of doing a /6 to 318 swap is getting the lopsided lump out of the car without trashing the bulkhead connector, after the 1st time you learn to disconnect it and push it inside the car.

Thank you for that tip.

Posted By: slantzilla

Re: Will a /6 904 bolt up to a 318? - 08/27/08 02:26 AM

Quote:

Quote:

About the hardest part of doing a /6 to 318 swap is getting the lopsided lump out of the car without trashing the bulkhead connector, after the 1st time you learn to disconnect it and push it inside the car.

Thank you for that tip.

Why would you trash the bulkhead connector? The engine leans the other way.

Posted By: vynn3

Re: Will a /6 904 bolt up to a 318? - 08/27/08 12:56 PM

Quote:

Why would you trash the bulkhead connector? The engine leans the other way.

Just more slant hateration, I assume.

If you want a V8, fine. No need to keep ragging on slants, though. Slants have been good, solid, reliable engines for 40+ years. And my mildly-modded is anything but slow.

But hey, if you break the bulkhead when you pull your engine, it's the engine's fault, right?

Posted By: jbc426

Re: Will a /6 904 bolt up to a 318? - 08/27/08 01:21 PM

Quote:

" lopsided lump" ?

Oh, you didn't just say that?

Let's race!!!

Attached picture 4645687-1968BarracudaConvertible004(Large).jpg

Posted By: slantzilla

Re: Will a /6 904 bolt up to a 318? - 08/27/08 01:35 PM

Quote:

But hey, if you break the bulkhead when you pull your engine, it's the engine's fault, right?

I don't even pull the hood off my Valiant when I pull the motor.

Just a question for all you 318 guys. How many Hemi owners have been afraid to race you for money after they saw you make a pass at Monster Mopar?

I know Slants aren't for everyone, but that isn't the motors fault.

Posted By: 340727dart

Re: Will a /6 904 bolt up to a 318? - 08/28/08 03:58 PM

Quote:

What you should do is find a rusted or wrecked car (or truck) with a good running 318 and good trans in it, take everything, and put it in your car.

I just now located a '77 Aspen wagon the guy is using for a daily driver with a 318/904 and will sell to me for $500.
And, another buddy has volunteered to haul the body to the scrap yard for me.

Posted By: ZIPPY

Re: Will a /6 904 bolt up to a 318? - 08/28/08 05:09 PM

Quote:

Quote:

What you should do is find a rusted or wrecked car (or truck) with a good running 318 and good trans in it, take everything, and put it in your car.

I just now located a '77 Aspen wagon the guy is using for a daily driver with a 318/904 and will sell to me for $500.
And, another buddy has volunteered to haul the body to the scrap yard for me.

That's the way it's done

Posted By: MarkZ

Re: Will a /6 904 bolt up to a 318? - 08/28/08 06:29 PM

Find an 85' or later M body. The 318s in them had the roller cams and swirl port heads (302 castings). They were only light on power due to the smog equipment, which I don't think would be following over with it anyways.

Posted By: patrick

Re: Will a /6 904 bolt up to a 318? - 08/28/08 07:03 PM

or keep the slant and get an A833OD manual. my duster is a stock 1bbl slanty with the OD tranny (3.09 first, 1.74 2nd, 1:1 3rd, .73 OD). with 25" tall tires and a 3.21 rear it keeps up with modern traffic just fine, and knocks down 24-26 combined mpg

Posted By: 340727dart

Re: Will a /6 904 bolt up to a 318? - 08/30/08 08:24 PM

I rebuilt the one barrel Holley a couple of days ago and that really helped with the idle and smoothness of the engine.
However, it is still gutless.
So, I had my wife floor the gas pedal (engine off, of course) while I looked down the carb throat.
It doesn't even go to half throttle. After inspecting it some more, I discovered it has an incorrect throttle cable on it. In fact, it looks more like an aftermarket transmission kickdown cable adapted to fit.
Anyway, I placed a parts wanted ad on Moparts last night and have already gotten several responses.
Thanks Moparts.

Posted By: scratchnfotraction

Re: Will a /6 904 bolt up to a 318? - 08/31/08 01:01 AM

good catch!

glad you found it,less than 1/2 throttle on a one barrel slanty would deff make it gutless

Posted By: plymouthfan

Re: Will a /6 904 bolt up to a 318? - 08/31/08 03:27 AM

I have the correct throttle cable on my slant 6 and it's still slower than molasses dripping uphill.