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318 WB vs 318 LA

firedome

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Fixing up a '64 Dodge 440 4 dr as a daily driver. The 318 WB has some mechanical issues that could be expensive due to the PO using low zinc oil. Money is an issue and I know WBs can be a bit pricey parts- wise. Am being offered a good LA 318 out of a '73 Dodge for very cheap. Anyone replaced a Wide Block 318 with an LA? I'd like to keep it original, but as I said $ is a major issue, and it's a 4 dr driver.
 
Should be no issues....both are small blocks.
 
I had one in a 66 Fury with a 318 poly. Not much will interchange as they are not the same block. I swapped a 440 in place of the 318 when it ran hot (before and after the rebuild) and showed significant signs of cracked heads, block, etc. I would check to make sure the motor mounts will line up the same. When you see the "K" frame, you'll notice it is different from later ones. Also, mine had a 727 tranny but many LA engines have the 904 which could make a difference as far as drive shaft length goes. You'll find the LA318 is much lighter as well. Heck, my 440 was lighter than that poly-head 318 so some minor changes to suspension were made. What type of problems are you having with the 318 in it now?
 
It's got significant valve noise when hot according to the PO - it's still on the way here from CO so I can't verify in person yet... I'm hoping it's just a stuck lifter or burnt exhaust valve, but he was using it as a dd and didn't use god oil with zinc, so am expecting the worst... I'd like to keep the WB, but if it's wiped cam lobes I don't know. Maybe I'll get lucky, but a cheap good '73 318 is available if I have to go that route...
 
The poly has solid lifters. Maybe some adjusting of the rockers will quiet it down?

As for a motor swap, I think you will find it drops right in. It needs to be a complete motor though. Stuff like exhaust manifolds, pulleys, etc., are not interchangable. The key is to make sure belts align before commiting to the LA motor. You may need to change the 'Y' pipe of the exhaust though. Not sure the manifolds dump out the same.
 
Firedome ,i have a poly in my Belvedere and i like it .i add the zinck additive every oil change ,I think only the truck 318 poly had solid lifters ,but i could be wrong
 
Could be the lifters. They are adjustable. Mine woul clack once in a while but not often and usually, once warm, they quieted down. If the sound is more than a clack, I'd be concerned about something more serious. The LA 318 will "disappear" inside the giant space left behind by the poly. I had more room, side to side, once the 440 was in place of the 318 poly. Who would have thought?
 
The A series 318 block is how much wider than the LA?? They have the same bore and stroke as the LA series.....yeah, the heads are way different and you can't interchange the cam between the two but the blocks are pretty much the same and could share many internal parts. The biggest difference between the LA and A engines is really the valve setup, skewed valve arrangement which had the exhaust valve parallel to the bore, and the intake valve tipped toward the intake manifold...and ended up with what's called the poly-spherical combustion chamber. The heads are large and wide and makes the engine look huge and I guess is why so many call it a wide block. For most, if there's an A block on one side of the shop and a LA block on the other, you wouldn't know one from the other unless you knew exactly what you were looking at. The blocks look just that similar once the heads are gone. Hell, you can even swap cranks between the two!
 
Half of what I read here today is BS and just wrong info. I don't mean this in a rude way.

Cranky, the blocks are the same physical size and will interchange many parts between them and though they may bolt on or in, they may not work. Currently I'm on my phone at work until tomorrow morning. So I can not go hunting around for the lengthy post I made with picture proof of the differences between them Poly and LA 318's.

The bottom line here is the swap will work and even better so IF you have the LA's tranny with it. I am not so sure a mid '70's trans will bolt up and work flawlessly with the older engine. This knowledge I admit is lacking to me at the moment.

The exhaust issue mentioned is dead on.

The Poly block is NOT wider than a LA
The head differences between the LA and Poly plus the way the intake bolts on give the appearance that the block is wider.

Part interchange between the two engines is well documented and just crazy (at this time on my phone) to repeat them here today.
 
Never done a trans swap from an LA to an A engine but hear it's a direct swap. Did a big block swap in 1970 into my 66 Belvedere that had a 318 poly. There were no problems at all installing the 383/727 except for stuff like swapping out the radiator and modifying wiring. Even used the same drive shaft as the poly engine also used a 727. Trans mount cross member and the original K frame stayed in place too. Now the 56 through 61 poly engines will throw a wrench at ya....

Went and found this site which is usually pretty good for info...
http://www.1962to1965mopar.ornocar.com/poly318_1.html
 
For me right now, in my head I know there are a few weird things with the old engines and the manual trans swaps. I forget if it applies to automatics. The older the poly, the more I can not remember. It has something to do with the rear flange size.

Swapping from small to big is no an issue with the drive train since it is the trans mount that is body specific and not trans specific. So long as you have the cars crossmember, it'll bolt up to what ever you have.
 
All I can go by is my experience owning one from 1984 to 1997. I could tell the difference. The weight and size were not the same but that's just my 2 cents. I'd say do some research and suit yourself.
 
It's kinda like the Hemi engine...pull the heads off of it and what you have...basically, is an RB block and that's what it is. The Hemi heads are huge which makes the engine look huge and very wide. Kinda like the 318 poly. A Hemi sitting side by side with a 440, they look almost identical unless you know what you're looking at. Many things interchange except for heads, cam and everything on the top end just like the poly teen. But of course the Hemi block (426) has cross bolted mains which are easy to see from the outside but a lot of people don't know about that.

One of the ways you can tell a pre 62 poly 318 is the timing cover interchange with the early 1956 to 1961 Poly blocks use the cast iron timing cover exclusively and have a unique water pump to those years but we're not concerned about the 61 and older teens here. Not real sure about if the K frame is different for the 64 poly vs the 66 (big change happened between 65-66 cars) cars but the 66 K wasn't a problem for the swap to a big block. Just had to get the BB motor mount brackets because the 318 brackets are different and the BB dropped right in. In this case, I don't see why the LA won't drop right in so long as you have the right oil pan.
 
If you like the poly engine (so do I) swap it for the LA, build it up over time and put it back in all badass. The 4" stroke Mopar crank will drop right in, they can be bored to 4" with no sweat and you'll have a fire breathing 402 kyoob poly no one else will have. I don't think camshafts interchange between polys and Las, but Oregon Cam can grind your core into whatever you want and they can reface the lifters too. The cam regrind is 75 and each lifter is 4 bucks. I think they take the same timing chain as the LA and I believe the distributors interchange. rumblefish please correct me if I am wrong. But I do know they can be real stump pullers. I look at them like the slant six. People always pull them out and throw them in the ditch for something "better" when they had something better all along.
 
The poly intake looks a hell of a lot wider, and makes the 2 bbl look even tinier than it does on an LA.
 
The intake is.... Kind of wider, it is, but... It's the angle of the mating surface to the head.. It's .... Ugh!

OK, I'm jus gonna have to dig up those damn pictures so I can show you all!

Bobby, camshafts can physically swap but will not operate the engine.
 
I'm going to try to keep the original poly 318 if at all possible... to confuse things even more we also have a '58 Windsor with a Spitfire 354 poly that's derived from the double rocker "hemi", and is totally unrelated to the Plymmie 318 poly, which was derived from the original Plym built 277/303, not the Dodge built "Hy-Fire" 241/260/270 poly or the Chrysler Spitfire 331/354 "big" poly... phew, this Mopar engine lineage sure can be confusing!
 
Firedome, here is what I can tell you; The blocks, LA and A may be the same size dimensionally but not after you add the poly's heads. Not all the internal parts are interchangeable. Intake manifolds, cylinder heads, (obviously valve covers) and for the most part camshafts do not interchange. I had to have a cam custom ground (ISKY) for mine, and I was able to locate a Weind 4bbl intake. If I could take a picture of the 2 bbl intake manifold, you'd see how much wider the poly intake is over the LA. The 318 Poly's valve location is different from that of the LA engine family. The intake valve is on one side of the rocker shaft and the exhaust valve on the other side whereas on the LA engines they are located on the same side. This is why the pushrods on the 318 poly are a straight line from the lifters to the rocker arms but angled on the LA engines. What I was trying to communicate to you was the cubic inches are the same but they are not the same motor and maybe, there might be some differences as far as motor mounts, height of engine, and so forth. I don't know that for sure because I went from the 318 poly to a 440 not an LA engine. My concern would be for the "noise" the engine makes. These engines had a reputation for being very tough, used in trucks, and reliable. I suspect mine bit the dust because the Chrysler dealer that rebuilt it did something wrong. It ran hot before the rebuild and even hotter after. Usually it did not boil but stayed close all the time. I took it to a place near where I work and they had it for months and found nothing wrong. I took it home and water shot out of the dual exhaust. They said it was condensation. It was more like a garden hose. A buddy and me took the valve covers off to adjust the valves and green radiator fluid shot up through the push rod holes. Oops. I had quite a lot of money sunk into it (I had a custom bracket made to switch it to a 4 bbl, cam, inake, carb, other work) and decided to pass on fixing it. I sold the cam, intake, carb, bracket, and so forth. We found radiator fluid under the intake, on top of the pistons, and on top of the oil in the oil pan. The heads and block could have been cracked, blown head gasket, etc.. but it was cheaper to buy a 440 ot of a Super Bee that ran good and swap them in place. Again, I was only suggesting you make some measurements and research this before the swap is all. Good luck and I hope it turns out well. My engine ran strong with the minor mods.
 
Yes it can be. All other pPply engines can interchange heads and other parts with the HEMI engine. Or some crap like that. I would like to get a hold of a old 354 Poly or HEMI.
 
I'm going to try to keep the original poly 318 if at all possible... to confuse things even more we also have a '58 Windsor with a Spitfire 354 poly that's derived from the double rocker "hemi", and is totally unrelated to the Plymmie 318 poly, which was derived from the original Plym built 277/303, not the Dodge built "Hy-Fire" 241/260/270 poly or the Chrysler Spitfire 331/354 "big" poly... phew, this Mopar engine lineage sure can be confusing!


The price for a 'standard' rebuild on a Poly is comparable to the price of an LA motor. Machine work is machine work, doesn't matter if it's a Poly or LA block. Parts 'can' be a bit higher...depending on who you get them from.
 
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