Seems the new Headgaskets have restricted water jacket openings?

you could go to www.moparchat.com then scroll down to & click on "circle track chat" then read thru Sanborns' cooling mods that are in a sticky at the top of the page. SB orientated but alot carries over & he's one of the sharpest in the country. it'll take you a good hour to read/reread/absorb it all but it is worth it then decide for yourself

I've wondered about this in the past. Even drilled a set of gaskets once to match the block. Seemed to work okay, but I can't suggest it. Last couple of times I've had mine off I've just installed them accepting the pattern and have found that it actually it stays cooler, and here's (I think) why: you want the water to run front to back through the block, then return through the head, utilizing the large passages at the front & back. I believe this keeps coolant moving all the way to the back, and keeps the water flowing in a pattern. If the coolant was allowed to flow down through the gasket too much, you'd get hot-spots as it wouldn't flow all the way to the back. At least this is what seems to make sense to me.

Basically, install them and ignore the desire to see the gasket passages align with the block & head passages. It works, don't sweat it.

Yeah they're supposed to be that way

Cylinder blocks are sand castings. In many cases the various holes in the block and the size of those holes are there to allow removal of the sand after solidification in the casting process. My advice would be to leave the head gaskets the way the engineers designed them. Mismatch or missing holes in the gasket are not a mistake.

OK THANKS!!!

This is nothing new , felpro, and others including current Mopar steel shim, headgaskets have been like this for decades and it doesn't cause problems in 99.9999% of cases .

Yes, think of the holes as metering devices.

R.

I agree, I just chiseled out a clearly original set from a 40 year old untouched 440 and they had the slots like that...

They are suppose the be restricted. You just want to have a bit of flow to prevent steam/air pockets. The coolant flow goes from front of block to back of block, up through back of heads to front of heads to thermostat.
Incorrectly enlarging the holes can show a lower thermostat temperature, but the back of the block will be running hot because you are bypassing the flow to the back of the block.

The exception to this might be increasing the hole to the next to last cylinder to help cool the center exhausts area of the head.

In my opinion, the small "slits" head gaskets were designed for '72 and later blocks shown in the bottom picture as they enlarged the water passages. The top picture is pre '72 block, if you put a those small "slit" head gaskets there is about 1/4" exposed, the rest is entirely covered, I believe the larger rectangular opening on the head gasket you posted was designed for pre '72 block. I have spoken to Greg at Superformance before as he has the template for the original Mopar Connection steel shim head gaskets, and his new reproduction have the larger rectangular slots.

However, I have run both on '68 block and have had zero issues with either design.

I had not seen that, Have been using 906 or 915 closed chamber heads on pre 72 blocks, interesting