Re: SV: 1962 Plymouth - 361 or 360?
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Re: SV: 1962 Plymouth - 361 or 360?




Knud-Erik, I'd like to throw in my 2¢ worth...

It's a '62 Plymouth, so the original engines would have been the 361 or the 318 Poly. Either of those engines is correct, the 360 is not correct.

Either engine will give plenty of performance, especially when aligned with the 4-speed which was not original... the 3-speed A745 would be the original transmission, they're cheap if you want to go original, but the only real benefit is that you don't have to enlarge the transmission hump in the floor.

Accepting that you have this non-originality in the 4-speed, which brings with it the tell-tale floor change that wasn't original either, then the 360 might be reasonable. However, I don't think so.

One benefit of the 360 not mentioned so far is the reduced weight at the front of the car. However, the Poly, while heavier than a 360, is also lighter than the 361. This will count when you attack some twisty road and the car wants to plow straight ahead with the extra weight of the 361 over the front wheels.

The Poly, however, is going to draw a crowd when you open the hood. Not many people have retained the Poly, even for cars that came with them. They've been hauled out in droves and replaced by big blocks. So to have one you'll find it draws its own attention. You'll also find, and Gary Pavlovich will agree, that it has some nice potential for producing good torque and power.

They use all the bottom end stuff from an LA, so the bearings, timing gear, water pump and so on are easily sourced. They do have unique head gaskets, valve cover gaskets, camshaft and pistons. That said, I believe pistons from an LA will work in them, I have seen one engine so fitted, not that I like the idea. If necessary, a fresh flycut in the tops would make them good enough... or you can readily order them, most makers still have them.

The downside is the lack of performance inlet manifolds. Weiand stopped making theirs, Edelbrock haven't made them for ages, but they are available if you hunt around eBay etc. Or you can join the queue for the new Air Gap-type of dual plane manifolds I'm planning to be making some time in the next year or so. I'm even going to make provision in these for injectors if anyone wants to run EFI.

I believe that a properly planned Poly 318 can readily produce 350hp with total driveability, more if you go with a stroker, for which cranks are readily available. Personally, I don't favour that option, though it's practical. I might feel differently about it in your case if you could get a 3.58" stroke with the 318 main journals in a forging. Here's the present options:

1. Forged 4" stroker crank, uses 318 flywheel (internal balance) - $678.67
2. Cast 4" stroker crank, uses 360-type flywheel (external balance) - $297.50

My views are my views, however. My nephew, who does know his stuff, would jump on the forged 4" stroker in a heartbeat, and he'd be happy to use the cast version in a road car too. You would need pistons to suit, of course, with a higher pin - these are available in both cast and forged, though flycutting might be needed if you're adapting LA or Ford pistons. Gary Pavlovich will be able to expand on this.

That will give you greater capacity than either of the engines you're considering, and you can do that with what is probably a better head, while the weight of the engine is somewhere in between the two others.

What are your prospects of picking up a Poly 318 in your country? Here I've been able to locate more than enough of them, though I would never trust a crank out of a truck version as they get over-revved on steep descents in low gear and tend to flog themselves to death, breaking the crank and ripping the main bearing webs out of the block. Same with LA truck engines.

The best ones would be out of a Case 1010, 1020 or 1060 Combine Harvester, I don't know if you have those there, but the petrol engined versions did use the Poly 318 and they never worked hard while they were, at the same time, probably better castings in the block (I have been told they were, but I've yet to prove it). These come complete with a flywheel, by the way!

I'm sending this to both the mailing list and your personal e.mail as I don't know if my mail gets through to the list. Please let me know if it does.

Ray


Knud-Erik Holm wrote:
I want the one with the best power, to my 4-speed man trans.
I will use the parts I have at hand, and what I can find for small money. I
have already sunk more than 10000 usd. In the car (incl.car purchase) some
will come in again when I sell the parts I don't need.
However I need to stop the money from flying out of my pants for the moment.
And then the issue, of balancing the flywheel or not? with the crankshaft or
not?

I am bying parts in USA, Denmark and Sweden.
-----Oprindelig meddelelse-----


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