NC Engine Builder
Grumpy Old Man
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Not 100% certain yet, but shooting for next week
318 build with dyno session
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Ant
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Oops! I forgot to move the decimal point to the right two times.
.
It shoud be Pi multiplied by 130.0. I'll just blame the error on my brain surgery, or someone unrelated to the situation, lol. Thanks for pointing that out, I fixed my guess.
PRH
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Any idea what size the headers will be?
NC Engine Builder
Grumpy Old Man
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Most likely a set of Doug's, 1 5/8 but I do have a set of the old hooker 1 3/4 ones, I might try both
PRH
Well-Known Member
That’s a better set of heads than I’ve ever used on a 318.
The question for me is how will the good heads/small cam combo respond on the short stroke/high RR combo.
One would think it should be a little screamer…….. it’ll be interesting to see if that’s how it will play out.
The question for me is how will the good heads/small cam combo respond on the short stroke/high RR combo.
One would think it should be a little screamer…….. it’ll be interesting to see if that’s how it will play out.
33IMP
Well-Known Member
Please do. I have been told often that my headers are too big, but I have not seen an apparent loss of torque. I'm my case, I'm using the headers that either came with the car, (custom builds)or swap meet specials. So, not much choice available, unlike, say, a small block camaro. (I even have some headers that I KNOW are too big, that I'm not using)
TT5.9mag
Two atmospheres are better than one
@NC Engine Builder is this engine going to a client or is there a possibility of more testing on it in the future?
NC Engine Builder
Grumpy Old Man
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The plan is to do the testing, then put the engine up for sale
B3422w5
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I assume you have seen this build( I bought the motor and ran a detuned, 231/237 cam version of it) in a 71 duster I had prior to my Dart
3400 with me, mid 11’s almost 116, flat hood, standard water pump and fan, exhaust, etc.
1 5/8 hookers on the dyno, cheapie Chinese dual plane I used like they did
https://www.hotrod.com/how-to/0901phr-mopar-318-magnum-engine
Magnum and not an LA?
NC Engine Builder
Grumpy Old Man
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I wonder as well. My theory was that the heads are pretty good for the cubic inch, and perhaps it will still make good power with less cam than would be typical. I will say I think the cam will be the limiting factor now, after hearing it run. It is quite docile.
B3422w5
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Yes, magnum. But same size( bore/ stroke etc) difference without a distinction
TT5.9mag
Two atmospheres are better than one
That engine was an LA roller bottom end with magnum R/T heads according to the article.
B3422w5
Well-Known Member
The roller bottom end doesn’t make it any more viable when running a flat tappet cam does it?
Trying to figure out why a 318 magnum block or 318 LA block would have a notable power difference power potential wise assuming the same cam was used(pistons, etc). Heads, sure. Those RT heads went 270’s at 600. Probably 40 or 50 horse better than the heads that will be used in this test, although they had a pretty suspect intake sitting on them
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Grumpy Old Man
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I would expect there would be zero difference in power strictly due to the block difference between la/magnum all other parts being the same
TT5.9mag
Two atmospheres are better than one
Absolutely zero difference in power production capabilities or viability.
TT5.9mag
Two atmospheres are better than one
The only difference between LA, LA roller, or Magnum is how they oil, how they’re set up for camshafts (roller with holes drilled and tapped for a spider) and maybe some metallurgical differences with regards to nickel content. But I personally don’t think there is enough of a difference to make a significant difference in strength. Also people claim the magnums had better production machining practices and therefore are better but if you’re building an engine you’re machining it anyway.
NC Engine Builder
Grumpy Old Man
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The other plus is the magnum is much newer, often the first rebuild on the block. The LA cores are so old now, getting a virgin one isnt common. Just like the core I used for this build, it had allready been rebuilt 2 or 3 times before I machined it
B3422w5
Well-Known Member
Stock top end stuff isn’t being used, so that isn’t a factor in this discussion.
My point is there isn’t any difference in power if either block is built with the same parts. Aftermarket pistons are going to weigh the same in either block.
The only difference is in what heads you choose to put on one or the other. You can put better heads on the LA and it will run better, you can put better heads on the magnum, it will run better.
You can use the same heads and they will run near identical
My point is there isn’t any difference in power if either block is built with the same parts. Aftermarket pistons are going to weigh the same in either block.
The only difference is in what heads you choose to put on one or the other. You can put better heads on the LA and it will run better, you can put better heads on the magnum, it will run better.
You can use the same heads and they will run near identical
PRH
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I’m certain a “racier” cam would make more power, but would limit the buyer pool for the engine some.
I actually like the XS cams…..especially with the 1.6 rockers.
While the 274 isn’t big enough to make all the power that could be had out of that long block, I think it’ll be enough to be pretty good.
Eons ago when I was building some circle track 2bbl 318’s, the cams were about 10-15deg more duration, and tighter lsa…….. but no concessions for street use.
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Grumpy Old Man
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I kept the cam conservative because I figured the eventual buyer will probably be more of a cruiser than a racer, and I wanted this build to be a "catalog" build anyone could duplicate without any trick parts or machine work. Maybe I'll build a racier version sometime later
I’m probably way over on my estimate ?
I had hoped the compression would have been a little more .
I was anticipating around 10.5 to 1 ,,, “Vain Hope”,,,Lol .
Tommy
I had hoped the compression would have been a little more .
I was anticipating around 10.5 to 1 ,,, “Vain Hope”,,,Lol .
Tommy
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Grumpy Old Man
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Yeah, it could stand more compression, but I would have had to mill the heads quite a bit, then possibly the intake, and that sorta deviated from the box-stock-bolt-together recipe
Right on every detail there .
I’m really pleased you are building a nice engine that is in the realm of possibility for any one to build at home .
Anyone can build an over the top race engine .
But,,,,it helps all the little guys here see that it can be done with good machining and sound parts shopping .
And good assembly of course as well .
Also,,,this will be read for years to come from anyone that types in the right search .
Tommy
I’m really pleased you are building a nice engine that is in the realm of possibility for any one to build at home .
Anyone can build an over the top race engine .
But,,,,it helps all the little guys here see that it can be done with good machining and sound parts shopping .
And good assembly of course as well .
Also,,,this will be read for years to come from anyone that types in the right search .
Tommy
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