Beef up the 318 poly,or put a 440 inn?

[kokxville]

Hey guys,

i'm in a dilemma right now.
I have to pull the poly engine out of my 1966 belvedere and put new gaskets,seals and freeze plugs in it,because it leaks every fluid what is in it(LOL)While i have the engine out anyway,i'm thinking of beef it up a little.I know performance parts are rare for these engines,but they do have a lot of potential.Now i have 2 440's laying around,and it crossed my mind of putting a stock 440 in it,i have one 1969 and one 1970 440 4bbl.But,what about the subframe,tranny,driveshaft,etc.I have a 8.75 rearend with the 2.76 highway gears.

What's the cheapest way to go and what do you guys think?

John

[maxwellwedge]

Well - I think the K-frame is the same. Trans (for sure) and driveshaft (probably) need to be changed. Trans mount may be ok. Of course you will need BB mounts. A 440 would mean a m/cylinder brake update for safety.

[Ghoste]

I admire very much the idea of trying to hot rod a poly but in a case where you're concerned about cost as well, it may end up being cheaper in the long run to go with the 440 IMO.  Of course I'm also attaching some headache cost to the task of making the poly run strong.

[greenpigs]

The only thing I have seen is a dual plane intake from the aftermarket for the poly 318, not sure on other performance upgrades.

Since you have the 440 I would swap one in and being a 69 or 70 is just more of a reason to do it.

[morepower]

Deffinately go big block 440. Dont waste any time with that 318 scrap it out. dodge chargers were meant for big blocks.

[djcarguy]

 if you 44o it ,you need ta change trans,radiator,wire harness ,exhaust and mounts... should also go bigger torsion bars and new and bigger better brakes as in disc,or 11 inch drums allthe way.and add sway bars and gas shocks..also all trim and parts for 44o.
   the old 318 is not a hot preformer ,but can move a 66 just fine and last for a butt load of fun miles..have had them in cars and trucks. they have 2 draw backs leaky valve covers and 2 tiny oil drain back holes in heads for top end drain back  ...i would save or sell 440's to go back into correct year muscle cars
          fix leaks and put some nice pipes on 318 and save a ton of gas and cash and drive that car.DJ<oregon

[elacruze]

I think I'd enjoy pumping the poly, and you won't see many of them at the car shows. They run just fine, and performance pieces are becoming a little more available. Saves the trouble of all the chassis changes, too.

[Ghoste]

As an aside, he isn't talking about putting the poly in his Charger, he's talking about it for the 66 Plymouth.

Say, didn't someone on this site build up a poly not long ago?  Was that you Elacruze or Rolling Thunder or??

[1BAD68]

I'd stick with the 318 especially if you plan on driving it much.
You'll be happy when gas is 5 bucks a gallon.

[elacruze]

As an aside, he isn't talking about putting the poly in his Charger, he's talking about it for the 65 Plymouth.

Say, didn't someone on this site build up a poly not long ago?  Was that you Elacruze or Rolling Thunder or??

I have a long-term 318 project, but it's not a Poly, just a garden LA.

[kokxville]

It's indeed for my 66 Belvedere,not my charger.That's getting a monster stroker 440,no doubt about that 
I stick with the poly then.I think the build is indeed more expensive than a 440,but with all the other things i need to exchange,i think it's more expensive at the end when i put the 440 in.
Anyone know a supplier or a junkyard that has upgrades parts for the Poly?
I'm looking for a 4bbl intake to start with.The carb on that thing right now is so small,it looks if it came out of a moped.Then i want a different cam and a set of headers.

Thanks.
John

[firefighter3931]

Do a leakdown & compression tests to the poly before throwing any money into it 

If i had a 440 lying around in descent shape there's no doubt that it would be getting installed between those fenders 



Ron

[Ghoste]

There were some applications for the poly that ran four barrels.  Marine use?

[Troy]

Hemigeno has a 318 poly with dual quads in his big truck. I think he's had to build/rebuild it about 3 times and I don't think it was cheap. It sure looks and sounds neat though!

For those not familiar, kokxville is in Holland so parts aren't as easy to obtain. Shipping pieces for a 318 poly might be cheaper than all the other parts necessary to put a 440 in the Belvedere.

Troy

[hemigeno]

Hemigeno has a 318 poly with dual quads in his big truck. I think he's had to build/rebuild it about 3 times and I don't think it was cheap. It sure looks and sounds neat though!

The poly engines have potential, but you have to be one determined individual to make it happen.  Parts are more difficult to find (especially camshafts, which caused 2 of my rebuild issues).  I wouldn't exactly discourage you from tackling a poly rebuild project, but don't assume it can be done at the same cost as a more traditional Mopar engine.  That ain't gonna happen -- but by the time you factor in some of the other components you'd have to change to swap in a B/RB engine, the costs might not be too far off.  Problem is, at the end of the day you'll still have "just" a poly engine.  If you're OK with that, go for it!

Regular add-on accessories like headers were not available a few years ago, but might be more commonly available now.  I think 4bbl manifolds can be found on eBay without too much trouble, and there were even aftermarket "performance" manifolds made by Weiand and Offenhauser many years ago, IIRC.

They are neat engines though.

[Cooter]

Mopar Muscle mag did and article on stroking out one of these with an overbore of .090..(Yes, .090), for an even 4.00" bore..
After all this money spent I can only speculte here ,but I'm guessing around $6500.00, this thing @ 402 C.I. only put out like 402 HP...

Factory cast iron manifolds and dual four intakes are all that's left out there as of right now..Last I heard, Weiand has about 25 Rough cast intakes just sitting on the shelf but refuse to cast any more, or fully machine the ones they have cast...Stock cast iron intakes(Power Pack) go for around $300-$500 and the dual four set up complete will run around $1200.00 with carb's..

The next hurdle is try finding headers for your poly-'66 Plymouth app. that aren't $800.00/set
Oh, and just wait until you go through the dreaded " I said POLY 318, why are you guys at Summit Racing/Jeg's/etc. still sending me LA style camshafts that fire a different order"...Finding ANY decent camshaft that isn't a factory regrind is gonna be expensive...Even at $5.00/gal for gas, a $6000.00 poly 318 getting 20 MPG and a $2000 440 getting 12 MPG, the 440  still comes out on top IMO...
Just dump the 440 in it and have some fun..

[greenpigs]

Just dump the 440 in it and have some fun..

I think you should sit down and write everything needed to do both the 318 build up & 440 swap. It will not be exact but better than guessing and should give you a $ amount to compare.

[djcarguy]

you say a monster strocker 440 in charger,may get 5 ta 8 mpg or 2 gas station per hour,,,lol.  the 66 belvedere could just be basicly stock 318 nice pipes and 15 ta 21 mpg and dependable more all year jump in and go drive,fun car less time and cash ta build and more for radical stuff on charger???   you asked,but bet ya will just do it and wonder later..   best with build....

[Cooter]

"What's the cheapest way to go and what do you guys think?"

Cheapest/Poly 318, and Performance don't even belong in the same sentence....

[ACUDANUT]

440...

[elacruze]

Right, back to 'cheapest';

Pull it, seal it, stick it back in.