318/410 What do you think (posting for a friend not my engine)

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Hallzy

Hallzy

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Align bore an hone zero deck the block, clearance the cylinder wLls for the rods with the 4" stroke , forged "H" rods and 10.5:1 pistons 4.040 bore ,w valve relief, forged steel crank, monster eq 2.02 intake magnum heads(dual pattern intake drilled) cnc runners and match intake. Melling HV oil pump, billet distributor, 4bbl holly efi live tbi. Adj Roller rockers on 3/8" studs, hd springs w dampers. roller lifters chain & cam w/ .505 in lift 114in/112ex 110 sep. SS valves 3 angle hardened seats polished chamber. Cradle the main journals and a splash shield. Port presurized oil onto all cam bearings and cross port coolant to back of head,
 
If you really started out with a 318 block, I’m def not a fan of boring the factory block out .130”(3.91>4.04).

4.04 bore x 4.00 stroke is 410”.
 
PRH said:
If you really started out with a 318 block, I’m def not a fan of boring the factory block out .130”(3.91>4.04).

4.04 bore x 4.00 stroke is 410”.
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Yes he is starting with a magnum 318
 
I bored out earlier 318 blocks to 4.040 with stock stroke, but I dont think I would do this with a that much thrust angle leaning on it w/4" stroke.

I'd have done .060 or maybe 4"..then it's only .020 more to 4.040 , it's a circle..so .020 aside =.040 larger ID...so I think I'd stay @.060...=3.97 close enough.
 
I take it he already has EQ heads in hand, but is the cam supposed to be listed as 314 degrees intake and 312 exhaust or is it supposed to be 214 intake 212 exhaust at .050 lift?
 
Big fan of the 4 inch stroke 318s. With good heads and cam it’s like having the power a well built 440 but with much better fuel mileage.
 
Very experience people expressed concern over the bore. People I personally would listen to. If it is already done and the block is finished machined. It is a good amount of money in machine work to walk away from, but if it splits a cylinder wall just think of the parts it can take with it. Seems like the old story about pay me now or pay me more later.
 
furrystump said:
Very experience people expressed concern over the bore. People I personally would listen to. If it is already done and the block is finished machined. It is a good amount of money in machine work to walk away from, but if it splits a cylinder wall just think of the parts it can take with it. Seems like the old story about pay me now or pay me more later.
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Thanks everyone's input is appreciated thats why I posted this to make sure for a friend that this build plan is actually sound or not
 
Hallzy said:
Thanks everyone's input is appreciated thats why I posted this to make sure for a friend that this build plan is actually sound or not
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Are magnum block cylinder walls cast as thick or thicker than the older ones anyway?
I would think they were pinching by then.
 
Nothing wrong at all with a 391 inch 318. Here's one in two and a quarter tons of fun! W150 extended cab with 33X12.50 tires, an NV 4500, and 3.91 gears on zero to 75 in second and third gear. I don't know what it's going in but I bet it's lighter than this hulk...
 
As I mentioned previously....... having the cylinder walls sonic tested would answer the question about whether or not trying for 4.040 made any sense.
 
Not everyone has a 340/400/440 engine to play with. I love the idea of the stroker kits to make something powerful out of the more common mopar engines. 383 stroked to 496, (exactly the same bore/stroke as the well respected 496 chevy stroker) 318 stroked to 392 (he he!) are great ways to make lemonade out of lemons (no disrespect intended).
I dont see any reason to try to bore a 318 to that size; it wouldn't surprise me if you could see thru the cylinder wall when done.
 
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Stock EQ heads? Not ported?
Cam duration is what now?
Type of cam? (Lifter style)

Sonic check the block for its maximum obtainable safe over bore. I don’t think you can go that far.

Not a fan of the intake and if the heads are stock, unported, why even bother with the build? While it will out torque any OE bore and stroke it will not HP them in any meaningful manor.
IF I was to make a suggestion (and here it is...) it would be to sell the heads and intake to roll the money over into a set of Trick Flow heads (rocker ratio of your choice) and a Edelbrock AG.

NOW! We are going to make some steam!
That would be worth the hassle and waiting time. He will long forget the price differences and wait time white the perma grin he will gain.
 
And that was the advice 50 years ago which was not 100% correct.
 
Garrett Ellison said:
Nothing wrong at all with a 391 inch 318. Here's one in two and a quarter tons of fun! W150 extended cab with 33X12.50 tires, an NV 4500, and 3.91 gears on zero to 75 in second and third gear. I don't know what it's going in but I bet it's lighter than this hulk...
Click to expand...

JUST what I wanted to see. I’m currently building a 408 for my ‘74 W200. It has a NP435 manual trans. 4.10 gears with 35’s.
It’s hard to keep focus that it’s gonna be a truck motor, It’s not for a bracket car. LOL. Hard to get outa that train of thought when I look at cams and heads, etc etc
 
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