I have a Mopar M block for my Hemi and everything was spot on. Came in at the 4.500" I only had to dust the bores to 4.503 to fit my JE Pistons.

Thanks, I am going to order from Jegs unless you folks have a better place for me to try. I appreciate the replies as my dream has always been a real hemi.

If you want 4.500" bore someplace else might be cheaper.

Any suggestions? Also can the 4.24 bore blocks go out to 4.500"?

Call Mancini first.

It's exciting to see some new cast iron. But the engineer in me sticks to the lower mass of an aluminum block.

IIRC the 4.24 blocks have full water jackets, the 4.500 blocks have siamesed cylinders. Someone is sure to correct me if that's an incorrect memory.

R.

Common casting, all Siamese, unfortunately there haven't been any water blocks since the prior generation piece marketed as 'megablock'.

I built a cast iron World block back in the early 2000s with the 4.190 rough bore block bought from Mopar per the customer not wanting to take a chance on the larger 4.490 bore block running hot, he ASSUMED that the smaller bore block would have water passages between he cylinders, NOT SO
There may have been around 1.0 to maybe 2.0 inch small opening, part of a very small water passage, down low on the center cylinders, maybe not

Cab, there was no such thing as a Mopar "World" block in the early 2000s.
it didn't exist yet.

If you meant the megablock as I am assuming you might have, then I would have to agree with your findings...the bore would not be a determining factor, small bore was available both ways.

I have a World hemi block in the shop that came new as a 4.24" bore. It is Siamese bore and has PLENTY of meat in the walls. I bored it to 4.5"...took about 25 lbs out of it which was a huge plus! These things are ridiculously heavy.

Looking at bill Mitchell's site, it states "In early July 2018 Gary Stanton had built and dyno tested the first BMP aluminum Hemi block and gave us his approval. It is now Mid August and we are happy to say that we have now just shipped our first 8 BMP aluminum Hemi blocks. We have decided to make a few small modifications at the foundry. Fortunately this will not take too long and Projected ship dates for new orders will begin in the later part of 2018. Due to the demand we are taking orders and asking for small deposits to guarantee a spot on the schedule." Although this is an aluminum block, it's nice to see some more options for blocks are starting to ship out again.

I thought Bill Mitchell had been making aluminum blocks for years?

He was, but he stopped making them a few years ago. He just started talking about producing them again this year with some improvements. Looks like he shipped some recently and is tweaking it again before shipping more, later this year.

Looks like I am going to pull the trigger and get one. I will call Mancini tomorrow morning. I don't have any good Dealerships around to get a block from. May try Jegs if Mancini can't get one.

your correct it was in the late 2000s, not earlier I built that one around 2008 or later with the block ordered from my local Dodge dealer, it was a World block
I did build several other N/A cast iron hemi blocks that where the earlier Mega blocks, one 4.25 bore and the others where either 4.320 or 4.380 bore sizes, CRS
I finished a pump gas EFI 572 C.I. motor earlier this year with one of the old World blocks that was 4.490 rough bore size, it made right at 799 HP at 6500 RPM, a little less torque than HP

Just took the plunge. Now I just need everything else lol.

I had a freind at a dealer look up the numbers. They are still saying not avalable product under developement.

Well I ordered mine from Jegs, and surprise surprise they are back ordered.


Called Mancini... Nothing

So at this point, if anyone has a usable ( not cracked or otherwise destroyed) hemi block send me a pm.

Thanks,

Darrin

Yes: I see on the JEGS site the 4.5 block is a bit over $4k and is supposed to ship in a week while the 4.24 bore is a bit over $3k and is supposed to ship in a couple weeks.
So that is a no-go? I was going to order one as well but I guess it isn't worth me phoning?

Did you speak to someone at Jegs or get an email notification?