Early 318 blocks

[cpearce]

Happy New Year to all,

First I wish to state I am aware that the only true way to check bore thickness is through sonic testing.

I have come across a complete 318 LA engine with a build date of Feb 14, 1969. The engine is carb to pan complete and is $200. Ive heard the early 318 blocks are known to be able to go to a 4" bore, sometimes even more.

I would be only picking up to tuck under work bench for some future project. Is this something worth picking up, what experiences have folks had with early blocks? Casting number is 318-9. Thanks everyone.

 

[yellow rose]

I've never seen it but I'm sure it's possible.

BTW, most of those early 318's I've seen were steel cranks.

 

[whitepunkonnitro]

The only 318 blocks that will take that .090 cut and not flinch are the 66-down Polys.
They are still pretty cheap and plentiful, and STRONG. High nickle castings that weigh a good 30 pounds more than the later LA blocks.

 

[Bobzilla]

I think most shops will charge more for that much bore increase, since it takes several passes instead of one or two passes, so even if it's possible it may not be cost effective. Still a decent price for a good 318 though. A well prepared normal overbore 318 will make plenty of power, so no need to spend extra for larger bores, even though it should help the heads breathe a little more through unshrouding.

 

[yellow rose]

I think most shops will charge more for that much bore increase, since it takes several passes instead of one or two passes, so even if it's possible it may not be cost effective. Still a decent price for a good 318 though. A well prepared normal overbore 318 will make plenty of power, so no need to spend extra for larger bores, even though it should help the heads breathe a little more through unshrouding.

If the bar is rigid and you have the right tooling you can set a sleeve in one cut. A .060 over cut shouldn't be a problem with the right stuff.

 

[Bobzilla]

Yup, so he'd end up with less than 4" bore of a 360, but still with a nice 318 build that breathes plenty good enough with decent heads, and only took one pass boring it.

 

[yellow rose]

Yup, so he'd end up with less than 4" bore of a 360, but still with a nice 318 build that breathes plenty good enough with decent heads, and only took one pass boring it.

I agree. The difference between a 3.970 bore and a 4.00 is very little in power.

 

[RustyRatRod]

The only 318 blocks that will take that .090 cut and not flinch are the 66-down Polys.
They are still pretty cheap and plentiful, and STRONG. High nickle castings that weigh a good 30 pounds more than the later LA blocks.

Somebody better let Hensley Motorsports know that, because they've been building 4" plus bore LA 318s for twenty years or more.

 

[cpearce]

Somebody better let Hensley Motorsports know that, because they've been building 4" plus bore LA 318s for twenty years or more.

So RustyRatRod,

Might this be one to grab? Do you happen to know what blocks they used.

 

[Demonic]

Many years back, a friend loaned me a Mopar book of some sort, it mentioned a shop called Mullen ( ? ) that built 318's using 72 and earlier blocks with a large overbore, like .090". I wish I could remember the title. Think it was softbound, brown in color.

 

[RustyRatRod]

So RustyRatRod,

Might this be one to grab? Do you happen to know what blocks they used.

I have no idea. I can tell you though, I have done some sonic testing myself on several early VS later 360 blocks and the general consensus was that the early ones were thicker, though I feel certain because of core shift, that was not 100% the case. Best bet is to sonic test them.

 

[rumblefish360]

Might this be one to grab?
Do you happen to know what blocks they used.

Question 1;
Maybe, maybe not. There is no guarantee on any block of any displacement.
Question 2; YES! The ones that sonic checked to be suites me for the over boring process. They wrote that. I’m not being a smart ***.

 

[JBurch]

Many years back, a friend loaned me a Mopar book of some sort, it mentioned a shop called Mullen ( ? ) that built 318's using 72 and earlier blocks with a large overbore, like .090". I wish I could remember the title. Think it was softbound, brown in color.

I think you mean: "Mopar Performance", published by S-A Design, edited and designed by Larry Schreib, covers small and big blocks.

 

[rumblefish360]

Mullen is a name in MoPar history.

 

[replicaracer43]

People will probably disagree with me, but I'd personally rather have my cylinder walls as thick as possible. Thick straight walls make more power than thin flexible ones.

 

[rumblefish360]

As long as my builder says there thick enough for the purpose at hand, I’m good to go. He builds winning engines, Not I!

 

[cpearce]

People will probably disagree with me, but I'd personally rather have my cylinder walls as thick as possible. Thick straight walls make more power than thin flexible ones.

I totally agree with this statement, I practice this myself. If however some of these blocks are as I've heard and can take a 4" bore while still maintaining acceptable wall thickness, they are then an affordable block for those of us with forged 340 main cranks.

 

[replicaracer43]

I totally agree with this statement, I practice this myself. If however some of these blocks are as I've heard and can take a 4" bore while still maintaining acceptable wall thickness, they are then an affordable block for those of us with forged 340 main cranks.

A standard bore 318 will gladly accept your forged 340 crank also...I get that guys want a "cheeper" 340, but it's not the best idea in the world

 

[cpearce]

Question 1;
Maybe, maybe not. There is no guarantee on any block of any displacement.
Question 2; YES! The ones that sonic checked to be suites me for the over boring process. They wrote that. I’m not being a smart ***.

Understood, thank you. As I said earlier sonic testing is only way to know for sure, I just thought perhaps certain years or casting numbers might point a person towards certain blocks worth checking. This particular engine is still completely assembled.

 

[RustyRatRod]

People will probably disagree with me, but I'd personally rather have my cylinder walls as thick as possible. Thick straight walls make more power than thin flexible ones.

I don't disagree one bit. I was just answerin the question at hand. Getting kyoobs and power by boring ain't the best way to do it by a long shot.

 

[replicaracer43]

Understood, thank you. As I said earlier sonic testing is only way to know for sure, I just thought perhaps certain years or casting numbers might point a person towards certain blocks worth checking. This particular engine is still completely assembled.

At that price, if it's not cracked, it's a good buy in my opinion

 

[cpearce]

Somebody better let Hensley Motorsports know that, because they've been building 4" plus bore LA 318s for twenty years or more.

The reason I bring this topic up at all is there is a shop in Lethbridge, Alberta, Canada that was building 434 small block strokers using early 318 blocks, I know this to be fact. These engines were run hard at the track and survived well. I am continuing to try to contact the gentlemen, just thought I would throw it out to my friends at FABO and learn from their experiences.

 

[RustyRatRod]

The reason I bring this topic up at all is there is a shop in Lethbridge, Alberta, Canada that was building 434 small block strokers using early 318 blocks, I know this to be fact. These engines were run hard at the track and survived well. I am continuing to try to contact the gentlemen, just thought I would throw it out to my friends at FABO and learn from their experiences.

Well, as more than one person has stated, it's not a bad thing to do, as long as you cover all the bases with good prep work, including sonic testing. As long as the cylinders are centered in the casting good, the water jackets will probably be thick enough.

One thing I have read.......and @krazykuda can probably confirm this, since he has worked for Chrysler, the "dash" blocks are not as good......and the higher the "dash number" is supposed to mean that's how many batches were used in a typical mold. In other words, an engine with a "-1"after the "318" casting in the block is "supposedly" better than one with a higher dash number. The later dash numbers were supposedly more prone to core shift.

At least that's what I've heard and read for years. Karl will know for sure, as he worked in the engine department. But, even with a low dash number......or not one at all, you still should sonic test before you bore that far. That's a BIG cut.

As long as everything checks out good, have at it.

 

[cpearce]

Well, as more than one person has stated, it's not a bad thing to do, as long as you cover all the bases with good prep work, including sonic testing. As long as the cylinders are centered in the casting good, the water jackets will probably be thick enough.

One thing I have read.......and @krazykuda can probably confirm this, since he has worked for Chrysler, the "dash" blocks are not as good......and the higher the "dash number" is supposed to mean that's how many batches were used in a typical mold. In other words, an engine with a "-1"after the "318" casting in the block is "supposedly" better than one with a higher dash number. The later dash numbers were supposedly more prone to core shift.

At least that's what I've heard and read for years. Karl will know for sure, as he worked in the engine department. But, even with a low dash number......or not one at all, you still should sonic test before you bore that far. That's a BIG cut.

As long as everything checks out good, have at it.

I agree completely, thanks. I too have read about the "higher dash number blocks" being less desirable. Im waiting on a photo of the balaner to determine cast or forged crank. For that price I think I will grab it, this stuff isn't exactly plentiful any more.

 

[RustyRatRod]

I agree completely, thanks. I too have read about the "higher dash number blocks" being less desirable. Im waiting on a photo of the balaner to determine cast or forged crank. For that price I think I will grab it, this stuff isn't exactly plentiful any more.

No it's not. If you have the storage space, it wouldn't be a bad idea to start a collection, IMO, of everything you can find.