Neutral balance to a 360 crank?

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I know for certain, that the 318 Mag and LA 318 use exactly the same crank/same casting number and all. No doubt about that one.
cant speak for the 360 but I know the balance amt is different between 360 LA and Mag versions. From what I understand the Mag pistons are lighter than LA ones. I have seen in catalogs where they tell you that you can use either piston in either 318 block as long as you use the rings that go with (wide or narrow)
I have a 360 Mag on the stand, that was bored 30-thou and has only a couple hours on it, damn injectors (2 of them) stuck wide open, and washed down the bores, break in oil came out as silver glitter. that was a 1st for me. I also have a set of 30-thou hypereuctectic and coated LA 360 pistons that I'd like to run in that Magnum block
I have another good, STD 360 Mag crank, and another 360 STD crank, this one an LA
Id like to run the LA pistons in the Mag block.
The LA was fresh then, with 6K miles at most my son decided that wasn't "enough" so he broke it back open and turned it into a 408.
problem is LA 360 takes a certain external balance/ Mag 360 takes different ext balance while a 318 is "scot free," internal balance.
trying to "use up" some of what I have laying around. and I want the flat tops in teh Mag, (I dont have an LA 360 block) for a perf increase.
To me (in general) the 360's thorn in its side as to why it has typically been nothing but a gas sucking pig is the low compression. I want to put the flat tops in, but build the long block (otherwise) as a Magnum motor, not as an LA..... Make sense?
I have a D150 with a /6 that will stay a /6. but I may be getting my 83 D250 back, and it is plum wore out. except maybe for the LA manifold bolt pattern EQs that I put onto that truck's original 318 back when I had it... which is still in the truck. now well over 200k, bottom end never touched from new.
I want to build a torque monster so tahts why I want to up the compression as a start. it will stay carbureted.
 
I bet if you used some light hypers and those 273/318 rods, you'd be real close on the balance. Being internally balanced, that is.
 
I bet if you used some light hypers and those 273/318 rods, you'd be real close on the balance. Being internally balanced, that is.

i used kb170 pistons....507 grams....scat i beams ...580 grams...still took mallory metal....less....but still took some
 
i used kb170 pistons....507 grams....scat i beams ...580 grams...still took mallory metal....less....but still took some

Yeah it's gonna take some regardless. That's a big change.
 
finding the early ones (the full floating ones from the factory) these days might be slightly easier than a set of 198s for my slant build... but still not exactly "easy"...this many years after they went outta production. what rods would a 72 360 have? (Im thinking all 360s had the "heavier" ones) I know where there's a wagon with a 360 short block in it, looks like never apart since leaving factory... only 360 I have seen without those damn dished compression (and power) robbing dished pistons that every other 360 I've ever seen apart has had.
 
finding the early ones (the full floating ones from the factory) these days might be slightly easier than a set of 198s for my slant build... but still not exactly "easy"...this many years after they went outta production. what rods would a 72 360 have? (Im thinking all 360s had the "heavier" ones) I know where there's a wagon with a 360 short block in it, looks like never apart since leaving factory... only 360 I have seen without those damn dished compression (and power) robbing dished pistons that every other 360 I've ever seen apart has had.

I have a set If you're interested. I'll never build a small block now.
 
finding the early ones (the full floating ones from the factory) these days might be slightly easier than a set of 198s for my slant build... but still not exactly "easy"...this many years after they went outta production. what rods would a 72 360 have? (Im thinking all 360s had the "heavier" ones) I know where there's a wagon with a 360 short block in it, looks like never apart since leaving factory... only 360 I have seen without those damn dished compression (and power) robbing dished pistons that every other 360 I've ever seen apart has had.

360s have the 645 rods.
 
I'm pretty sure that 273 rods are heavier than Eagle SIR & Scat I beams. For reference, 360 +.030" flattops by Probe are advertised at 476 grams, SRP flattops are advertised at 489 grams, Ross is 484 grams - lighter than any other off-the-shelf pistons I've been able to find, forged or hyper.
 
I'm pretty sure that 273 rods are heavier than Eagle SIR & Scat I beams. For reference, 360 +.030" flattops by Probe are advertised at 476 grams, SRP flattops are advertised at 489 grams, Ross is 484 grams - lighter than any other off-the-shelf pistons I've been able to find, forged or hyper.

I don't remember. I used to know. I do know Mopar Performance offered a reman version of them that was REAL nice. ARP rod bolts, cintered bronze bushings. They were sought after for a while. They're still a "good bit" lighter than the standard 340/360 rods.
 
I don't remember. I used to know. I do know Mopar Performance offered a reman version of them that was REAL nice. ARP rod bolts, cintered bronze bushings. They were sought after for a while. They're still a "good bit" lighter than the standard 340/360 rods.

They weren't reman but a special forged rod based on the 273 and made from the better 4340 material with "Mopar" forged into the beam! Eagle SIR are made from the lesser 5140. I think the Mopar Performance rod can be made lighter than Eagle H-beam rods by removing a lot of material, mainly the balance pads. I have some but never got around to trying it.
 
They weren't reman but a special forged rod based on the 273 and made from the better 4340 material with "Mopar" forged into the beam! Eagle SIR are made from the lesser 5140. I think the Mopar Performance rod can be made lighter than Eagle H-beam rods by removing a lot of material, mainly the balance pads. I have some but never got around to trying it.
Can you post a picture of said rod? I’d like to see the casted “Mopar” rod. :)
 
Can you post a picture of said rod? I’d like to see the casted “Mopar” rod. :)

This is a pic from the ad 70aarcuda had from which I bought the rods. Mopar Performance P4532685 / P4876283 / P5249741

I believe all 3 part numbers refer to the same rod, just changed over the years.


4340rod-jpg.jpg
 
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