400 bigblock 1971 August 22nd production date

[sebring+]

Ok guys I've got 2 blocks machined .030 over by a guy that knows his stuff.

I want to keep one and sell the other.

1. One is 7●22●71 230 casting.
2. Other is a 1976 block. Don't remember date and casting off top of my head.

I know the early 1971 block is more desirable but how much?

The difference in the sale value will be what determines which one I sell.

Any idea of values?

Thanks.

oh, I have 2 because the builder(a lifelong racer and machinist) tried to swap blocks on me. I kept the swapped block and my original early block. He didn't say a word. I was pissed and he knew what he was doing.

 

[Budnicks]

the '230' 400 block is the best block, according to all the experts
thickest & the strongest thick main webbing of the OE BBMs
that's the one I'd used hands down to build
I haven't bought any in so long I'm out of touch as to price

 

[IQ52]

Yeah the 1976 block isn't worth squat. I wouldn't put anymore than 750 horsepower through it.

Oh, the same goes for the 1971 block too.

 

[sebring+]

So a 71 400 isn't worth squat?

 

[Todd Millican]

So a 71 400 isn't worth squat?

I think, or at least hope he was kidding. I wouldn't know the values either, but 750hp is a damn lot to put through anything....without major expenses....I think you have a keeper for sure.

 

[GTX JOHN]

i would pay $400 for the 71 block and
pick it up if in So Cal

 

[cdr]

The main problem is the 71 230 block is known for bad core shift, some are pretty good & some are bad, sonic checking will help determine if its usable , the 76 block needs to be sonic checked also, as IQ52 said, no matter what dont build a high HP race deal on either .

 

[Runner 68]

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

 

[GTX JOHN]

The Core Shift is always a gamble with no rhyme or reason whatsoever
and every year and size Block can have favorable (Thrust side) or unfavorable
core shift. You can buy a sonic tester for $150 or less in E bay or Amazon and
if is a vital tool for a serious racer.
However, to get the most accurate comparison the block needs to be at least Hot
Tanked and really much better Acid Washed so that you are not picking up a lot
of rust affecting the reading.
Over the years, I have kept about 1/3 of the blocks that I have tested and sold the
rest to street and restoration guys. They are fine for that application = Just not for
the Stock/Superstock racing we do!

 

[sebring+]

OK, I'm getting it...
There isn't much of a difference in value between the '71 and '76 block.

I will keep the original #'s matching early '71 block with my 1972 sebring plus where it belongs and sell the 76 block.

I have heard so many stories of the '71 early blocks being GOLDEN that I thought it may be worth a lot of $$$.

I'm sure both blocks are GOOD TO GO. The machinist/builder does great work and has a good reputation but also likes to swap better parts for average parts. He also tried to swap my 906 heads!

Both are .030 over and are planned for my '72 sebring plus as a daily driver.

 

[BSB67]

So the machinist is really good, just dishonest.

So you already have the pistons?

 

[sebring+]

So the machinist is really good, just dishonest.

So you already have the pistons?

YEP.
VERY GOOD WORK BUT WILL TAKE THE BETTER STUFF AND REPLACE IT WITH COMMON STUFF.

But very good work and very knowledgeable.
I have everything.
All good.
Plus an extra block

 

[furious70]

The 230 block with good mag and sonic tests is definitely worth more on the market. I don't think anyone meant to say otherwise. It just needs to be tested. Other people will pay a premium for it even a couple in this thread won't.

 

[LemonWedge]

Not all 230 blocks are thick web castings. Physical check is needed. If it’s not, then there’s literally no difference between the two in my book.

 

[sebring+]

Thanks!

 

[PROSTOCKTOM]

If it has the thick webs and it sonic test well it might sell around $800. However a $400 offer for an unproven block is a more than fair offer given that it could actually be a bad block with excessive core shift.

Tom

 

[oldkimmer]

Always keep the numbers matching engine for your car weather u use it or not. Kim

 

[sebring+]

Always keep the numbers matching engine for your car weather u use it or not. Kim

Ya,
Decided on keep the '72 sebring original.

The only things I changed:

-1968 ported 906 heads
-Sure grip
-Cut in '71 side markers
-'71 rear bumper(I like the look better)


Actually getting something accomplished after 22 yeaars

 

[66Satellite47]

Not all 230 blocks are thick web castings. Physical check is needed. If it’s not, then there’s literally no difference between the two in my book.

Lemon, I was thinking the exact same thing, not all 230 castings had the thick webs. No idea what Mopar was doing with casting numbers. Don't recall what the casting number was on my first 400/452 motor. It was a '72 400 out of a Sheriff car. At least 500 hundred runs at 7000+ rpm. Eventually found #4 main cap in two pieces. Still ran fine, but the steel crank was worn out. I presume that's why the cap broke.

 

[moparmarks]

230 blocks casted after 10/17/71 are not the cold weather blocks.