So mid to late 70,s 440 blocks are actually better than the earlier 440,s?

[70ChargerRT]

Had a discussion with a Mopar buddy of mine and I told him about the thought of building another engine, a stroker and so forth. He said well if you ever thought about just doing another 440 block I have some really good mid to late 70 standard blocks. I said well I really appreciate it but if I’d did use another block it would be one of the earlier 440 blocks and then he told the later ones are actually a tad better. I said, how so? He went on to tell me that that motor mount ears are way thicker and the block cools better with bigger cooling holes in the block. I replied, I thought they were thinned wall and he said no that they weren’t. He said the bigger cooling hole was closer to the cylinder walls but he’s never ever heard about any problems from it. Is this true what my buddy just told me about the later blocks?

 

[Lefty71]

Many later blocks are "cold weather" blocks. The sides by the freeze plugs are visibly thicker. They are all heavy duty tho really, and you need to state your horsepower intent and race duty before worrying about the vintage.

 

[Kern Dog]

Had a discussion with a Mopar buddy of mine and I told him about the thought of building another engine, a stroker and so forth. He said well if you ever thought about just doing another 440 block I have some really good mid to late 70 standard blocks. I said well I really appreciate it but if I’d did use another block it would be one of the earlier 440 blocks and then he told the later ones are actually a tad better. I said, how so? He went on to tell me that that motor mount ears are way thicker and the block cools better with bigger cooling holes in the block. I replied, I thought they were thinned wall and he said no that they weren’t. He said the bigger cooling hole was closer to the cylinder walls but he’s never ever heard about any problems from it. Is this true what my buddy just told me about the later blocks?

For years, we were fed that "thin wall 440" bullshit. I think it started with some idiot from Direct Connection, maybe Larry Shepard?
Regardless...
Mopar Muscle and Mopar Action magazines looked into this claim years ago and determined that the ALL blocks had similar wall thickness but the later blocks had slightly softer metal in it. The later blocks had reinforcement ribs horizontally near the core plugs too. The webbing in the 400 blocks (Early, as in 1972-73) was supposed to be thicker than the 74-78 400s.
The heaviest blocks that were measured for the comparison actually were the later blocks cast after 1976. 224 lbs for one of the bare 440s with main caps. My machinist has often mentioned how hard the engine blocks for Mopars were compared to other brands.

 

[70ChargerRT]

For years, we were fed that "thin wall 440" bullshit. I think it started with some idiot from Direct Connection, maybe Larry Shepard?
Regardless...
Mopar Muscle and Mopar Action magazines looked into this claim years ago and determined that the ALL blocks had similar wall thickness but the later blocks had slightly softer metal in it. The later blocks had reinforcement ribs horizontally near the core plugs too. The webbing in the 400 blocks (Early, as in 1972-73) was supposed to be thicker than the 74-78 400s.
The heaviest blocks that were measured for the comparison actually were the later blocks cast after 1976. 224 lbs for one of the bare 440s with main caps. My machinist has often mentioned how hard the engine blocks for Mopars were compared to other brands.

Yeah I was absolutely clueless about the later blocks, been fed that same bullshit.

 

[RemCharger]

They should still all be sonic checked anyway. For big power builds

 

[33 IMP]

440 source has a good piece online about big block blocks. They dispute the "thin wall" bullshit too.
But they do a great job of pointing out which blocks have the most meat in the lower end saddle area.
Winner! Is certain of the early 70s 400 blocks.
The article is posted at 440 sources site.

 

[BeepBeepRR]

440 Source.com Everything you've ever wanted to know about blocks and more....

There is no such thing as thinwall blocks. They DO NOT exist.

We have sonic checked over 50 blocks, and have found absolutely no evidence that later model blocks have cylinder walls that are any thinner then earlier blocks. In fact, we have found later blocks to have less core shift, meaning the cylinder walls are of a more uniform thickness all the way around. This makes perfect sense, considering that B engines were in production for over 2 decades. During this time, it would be expected that there would be small improvements in the technology of casting processes, quality control, etc, which would help create a better product.

There was also an article from Mopar Action magazine by Andy Finkbeiner of AR Engineering in which they sonic check 20 blocks and come up with the same findings we did. They also explain how statistically 20 blocks is enough of a sample to estimate the rest of the 440 blocks out there. We've tested over 50 with the same results. This article also has some great info regarding hardness of the iron used, in which they find that the earlier blocks do have slightly harder cast iron, by about 10%.

Another issue is block weight, or the quantity of cast iron which is actually used in the block. Like the Mopar Action article, we have weighed many blocks and have found later blocks to weigh more, or have more cast iron in them. Since the reasoning behind thin wall blocks is that the factory used this practice in the late 70's to save money on iron (which is a known fact with SB Chevy engines), the fact that later blocks weigh more shows that Chrysler had no intention of using less iron to save money. Which is great news for us racers and performance enthusiasts.

So, the bottom line? Save and use those late model blocks. And go .060" over with 'em all day long. Also on that note, we know of several machine shops that have been going .060" with late model blocks for over 20 years with no problems.​

 

[451Mopar]

I think if your 600 HP or less and only 0.030" overbore any big block should be OK?
I would sonic check the bores just for the information in case it has real bad core shift

 

[gkent]

I have a later block. Punched it .055 over with no problems. Sonic checked first. As an added bonus - my cam slipped right in the new bearings - no core shift issues !!

 

[6PKRTSE]

They are all just used cores until sonic checked. Once sonic checked good. Then it's a good builder. I have seen many blocks go totally against everyone's so called theories and/or rumors of what is better or not.

 

[j-c-c-62]

A seldom if ever enforced Federal emissions requirement is the car must be equipped emissions wise as per the year of the engine, which the casting date pretty much indicates.
So, if they ever want to get selectively picky, anyone with say a 1978 440 block in a 1962 car driving on the road will be in a heap of trouble.
I know of no law that prevents removal of excess weight on a block, like casting date numbers.

 

[33 IMP]

Even in california, no one's gonna look at engine numbers on a smog exempt car.

 

[j-c-c-62]

You understand, the engine date determines whether car is smog exempt or not.

History tells us that overlooking might change, or maybe not. Might want to see what the decades old Diesel delete manufacturers/tuners have to say on the matter.