Winter Block??

[Cuda416]

Someone close to me is selling what sounds like a standard bore  '71 400 block. There is a "3X" on the block and he mentioned he thought it might be a "Winter block". I've never heard of such a thing before so I am hoping someone explain this.

I plan on building a 451 stroker from the block

[Chryco Psycho]

Being a 71 it could very well be the xxxx230 casting , if so it is one of the strongest blocks made by Mopar .
 I have no clue on the winter block ?

[Cuda416]

Thanks, that's the block he has. I have been reading a bit and I think the 'Winter Block" is like saying "440 six pack block".  it's not really different at all. Unless your a jackelope.

[Chryco Psycho]

the only thing I can come up with is the 230 castings were only made for a short time , maybe they were only cast through the first winter of production ?

[Moparal]

The cold weather blocks have thicker main web bosses. They quit making them after sept or early october of 1971.  They  ARE a stronger block.  So not all 230 block castings are cold weather blocks

[ChallengerHK]

Learn something new every day.

[Cuda416]

The block in question has a date code 9/9/71. I thought all 400 blocks had full thicknesses webbing. Anyway, this sounds like a winner in any case. Think Ill pick it up.  Thanks for the input guys.

[Cuda416]

Well whatever a "Winter" block is, I seem to have one now. I bought it last night. Nasty bright green color from some attempt to look cool I guess  Thanks for the input guys!

-C

[73EStroker]

All of the above features and my 230 casting 71 block also has some extra external cast in ribs running along near the top of the block on the outsides. I had mine checked before boring and it could have gone out .060 but I only bored it to .040.