440 block date question

[Sir Dodgealot]

Hey yall. Planning to drop a 440 in my 72 charger 318 car. My question is wut year did chrysler start the thinner walls for tha big blocks? I've been told 72 or 73 is tha latest year id want to buy to build a high performance motor. Any help is appreciated. Thanks

 

[66Satellite47]

I sonic checked a bunch in the mid '80's & all were pretty much the same '67 - 74, the couple of later ones were thinner, as I recall.

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I sonic checked a bunch in the mid '80's & all were pretty much the same '67 - 74, the couple of later ones were thinner, as I recall. Sonic check to be sure what you've got before spending a lot on it.

 

[Daves69]

You might check 440 source for their take on it.........................

http://www.440source.com/blockinfo.htm

 

[mopar12372]

the block thing is a myth. sonic check any block to know what direction you can take . core shift / bore
67 down blocks dont have the cast support into the block and the later the block the more support on the side of the the block 68 up have it

ask your self this the 413 /426 did the people back then worry about what you do ? answer nope . raced the engines for YEARS . talk to a old timer and all this myth will go away

 

[lewtot184]

'76 and later were the "thinner" ones. seems to be a lot of different opinions on this. i know of some later blocks that were thin but i don't think that means all were. it's my understanding that the later block's material was not as good as the earlier and that may be why mopar recommended no more than a .020"-.030" overbore. if you check back into service manual specs and factory recommended over bores back in the '60's and maybe early '70's no more than .040" over bore was recommended.

 

[terzmo]

I have heard several times the mid 70 blocks are stronger than 66 to 69......The blocks are all the same as far as I'm concerned with the HP blocks having head work and different cams...blocks are no different from reg or HP...if the numbers don't match...who cares except the people who MUST restore to original.....or someone who NEEDS a numbers matching car...good luck

 

[1966satellite]

It's my understanding that the only changes to the 440 block were to increase the thickness of the motor mount flanges and "siamese" the water passages. I think that happened in the early to mid "70's. I don't believe anything was ever done with the wall thickness.

 

[Sir Dodgealot]

440 source says no difference except that later blocks are probly better than earlier as the thickness is tha same as the earlier, and actually more uniform thickness throughout becuz of improvements in manufacturing technology. Also the motor mount flanges were began being made thicker in 75 which is another reason to use a later coded block. Also HP has nothing to do with the block but the heads rods etc.

 

[moparmarks]

The mid-70's thin blocks is a lie. Been proven over and over again.

 

[IQ52]

I have had 40 some 440 blocks sonic checked and there is no consistent thin or thick wall blocks. Every block needs to be sonic checked if you are going to push a bunch of power through it.

 

[monaco66coupe]

, as emission requirements Increased, the 440 was consistently leaned out, which made them run warmer. Consequently, The water jackets changed to Increase coolant flow. The mid 70's engines had frequent warranty Issues with the rotten egg
smell, a sign of a problem with the catalytic convertor and emissions overall. My 74' HP block has an additional water passage way in the middle of the block to help deal with that. Now the slant six engines later in the 70's cracked heads all the time, because those engines had the same problem. I just remember visiting the Dealer back then, and the mechanics complained about them all the time. My friend back in 1980 had a 78 diplomat slant six that went through three heads by 50,000 miles. So some of the myths of thinner blocks come from this issue. I like the 74' block, as more coolant flow is better. I just don't put all that crap back on the engine. With a Lower coolant temp, and richer mixture, they are great Blocks. Just my experience.

 

[Pops1967GTX]

http://arengineering.com/tech/sonic-checking-the-mopar-big-block/

 

[monaco66coupe]

thanks pops1967, that is a great article. 15 LBS difference between a 383-440? I had assumed the difference was much more.

 

[Daves69]

I have had 40 some 440 blocks sonic checked and there is no consistent thin or thick wall blocks. Every block needs to be sonic checked if you are going to push a bunch of power through it.

"Thin wall" line maybe used as a disclaimer for possible casting imperfections?

 

[Cranky]

thanks pops1967, that is a great article. 15 LBS difference between a 383-440? I had assumed the difference was much more.

Yup...not much difference in weight between the low and raised deck engines. Most of the weight difference is in the block, crank and rods. Rods not much. The pistons in a 383 are also a little lighter due to bore diameter and compression height being smaller and shorter.