Strange 318 Block

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mchartier105

mchartier105

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Hi, I recently was going through some of the stuff I have around and noticed something strange on a 318 block I have, the casting number is 4104230 but there's a large R casted before it.

Searching it up I find that it should be either a "race block" or a later 80's stock 318, yet the casting number on it is 79, and there's also no X cast into the block, and all the basic stock 318 blocks I've seen with this casting number don't have a big R cast into them, so I'm very confused with what I have.

Mostly just wondering if its any stronger than my 318 magnum block I'm using now, as I'm planning on turboing it. Any help is very appreciated, thanks.

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mchartier105 said:
Hi, I recently was going through some of the stuff I have around and noticed something strange on a 318 block I have, the casting number is 4104230 but there's a large R casted before it.

Searching it up I find that it should be either a "race block" or a later 80's stock 318, yet the casting number on it is 79, and there's also no X cast into the block, and all the basic stock 318 blocks I've seen with this casting number don't have a big R cast into them, so I'm very confused with what I have.

Mostly just wondering if its any stronger than my 318 magnum block I'm using now, as I'm planning on turboing it. Any help is very appreciated, thanks.

View attachment 1715319302 View attachment 1715319304 View attachment 1715319305 View attachment 1715319309
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Just Googled that Block Number and it shows: Race Engine
4104230 318 LA Race Engine

Info located at:
Mopar Engine Casting Numbers

Looks Interesting, wonder what is different about it ? Maybe a little more Nickle in it ?

Good Find . . .
 
That's what I'm curious about, apparently those casting numbers were used on mid 80s 318 blocks in trucks also, but without the R, and I can't find anything on the block that seems "better" than a normal block, the main webs don't seem any thicker, and the bores aren't siamesed, so I'm curious what's different about it, if anything.
 
My block doesn't have an X cast into it anywhere though, I thought if it doesn't have that X that's its basically just a stock 318 block, am I wrong? What's better about this block?
 
mchartier105 said:
My block doesn't have an X cast into it anywhere though, I thought if it doesn't have that X that's its basically just a stock 318 block, am I wrong? What's better about this block?
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That part number is a race block number.
 
I am betting it is a High Nickel content in the block cast mix. The chevy 350 guys want the 010 block that has the high nickel content for their performance builds. I honed one of these and the Cylinder Walls are really really hard.

A good simple test might be to see if it has very little ridge in the cylinders at the top compared to a regular 318 cast block that usually gets a pretty good ridge at the top of the cylinder after a lot of miles.

Will be interested to hear what you find out more on it. Pretty Unique !
 
George Jets said:
I am betting it is a High Nickel content in the block cast mix. The chevy 350 guys want the 010 block that has the high nickel content for their performance builds. I honed one of these and the Cylinder Walls are really really hard.

A good simple test might be to see if it has very little ridge in the cylinders at the top compared to a regular 318 cast block that usually gets a pretty good ridge at the top of the cylinder after a lot of miles.

Will be interested to hear what you find out more on it. Pretty Unique !
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There is a slight ridge, but I can't feel it by rubbing my finger over it, I'm thinking a tiny bit of scotchbrite would get rid of it, you may be onto something.
 
I think in this case, that is some sort of warranty block and the R means replacement. All the race blocks I am aware of had 4 bolt main caps. The X would indicate a race block. There is no X.
 
There's also an R on the rear where the bellhousing bolts on, if that makes any difference at all.

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Think it's just a good race block mopar puts on their parts shelf, kind of like the warranty blocks with the blank VIN stamping area.

Mopar had them on the shelf ready to go when someone needed one. I have a Warranty Block that came out of a 76 D-200 4x4 low miles, like no ridge. Got that one up and running now sitting in my 76 D100 Build soon to be on the road.

One check see if it has any vin numbers on the lower right front of the block and go from there.
 
George Jets said:
Think it's just a good race block mopar puts on their parts shelf, kind of like the warranty blocks with the blank VIN stamping area.

Mopar had them on the shelf ready to go when someone needed one. I have a Warranty Block that came out of a 76 D-200 4x4 low miles, like no ridge. Got that one up and running now sitting in my 76 D100 Build soon to be on the road.

One check see if it has any vin numbers on the lower right front of the block and go from there.
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Where exactly would I be checking for that?
 
mchartier105 said:
There is a slight ridge, but I can't feel it by rubbing my finger over it, I'm thinking a tiny bit of scotchbrite would get rid of it, you may be onto something.
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Just Great ! I would bet you Lunch that it is the High Nickel 2 bolt main race block. 318 blocks are built tough to begin with, ever compared one to a 289 ford block. The ford block looks like a toy and cracks between the compression side of the cylinder and the water jacket, pretty much junk after that.

Good 318 Block and add a little more nickel to the cast mix and you got a tough one. Always enjoy retracing the mopar engineers footsteps, those guys could hardly wait to get to work in the morning to continue building the mopars.
 
That is NOT a race block, it's a common, run of the mill 79 318 block. The x blocks had the same casting numbers making it confusing, but there is nothing special about the block pictured
 
replicaracer43 said:
That is NOT a race block, it's a common, run of the mill 79 318 block. The x blocks had the same casting numbers making it confusing, but there is nothing special about the block pictured
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'Swat I was thinkin.
 
Read somewhere that the R blocks were special castings with provisions for 4 bolt mains, but that only the 340's actually drilled with them.
 
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