Crossflow tips!!

Have you tried laying a US head gasket on the the Au heads deck to see how the passages line up?

I dont have a spare head gasket around to compare but from Jacks write up 3 of the US passages can be used by drilling out the head, but originally you have 6 which greatly decreases the coolant flow to the head especially since the 3 made into the head are much smaller than the filled in ones. Hence why i got the extra block to experiment with. It shouldnt matter if i tap into the cooling passage in the side of the head or throught the deck surface. The only limitation to going in from the side is space since it will have a manifold there.

Where in pecticular are the oil galleys in these engines just so i dont poke a hole and make my radiator an oil cooler :roll:

The side were the oil filter mounts than if you turn your block over and looking at were the oil pump mounts and with the main caps off you can see the locations most of the oil galleys.

Thank you i will check that out. Today I am going to put the head back on and see how far off the water jacket of the head is from the stock water jackets, and if all the of the AU heads passages hang out over the side. I would be a pain to seal but technically the head could be build up via welding to create enough metal at the US block passage locations to allow a hole to be drilled into the head and used. Or if There is enough meat on the block on the other side to drill into the blocks water jacket and use a few of the stock AU ports.

Otherwise the only option I see is to drill tap the water jackets and use external lines to provide more flow between the block and head.

Looked at the head on the block some more and there is no practical way to make anymore of the the stock ports line up. there is no cooling passage above the other 3 US ports and all 6 of the AU ports hang out over the side of the block as shown in these pictures



But i did have a new idea from this round of fitting up the head.

If i have the original passages in the head welded up and the bottom corner milled to a 45 degree angle it would allow a nice long flat surface to drill and tap a flair into. Then since behind each of the cylinders there is the water jacket shown in this picture



So then tap into that water jacket put in a line and alacazam more coolant flow. Tapping in fitting to slide flexible line over would be easiest, but with the angles needed I think metal lines might be better suited. Also these lines would be very close to the header which might allow extra unwanted heat into the lines. So a heat shield and ceramic coating might be required.

There are several coolant passages that line up already. The main one at the rear of the head and block is no problem and is fine just as it it. That's the primary one anyway.

Then there are two more on the left side of the block that will work as well. There is a third passage on the left side of the block that has to be plugged because it matches with an oil drain hole in the head.

At the front of the block there is a coolant bypass hole that needs to be added to the gasket and the head.

BTW, don't drill the gasket; get a punch. A laminated composite gasket will get all screwed up if you put a drill to it.

The holes that concern me are the ones on the right side. After you weld up the ones in the head, there is nothing on the right side of the head to help alleviate steam pockets in the head. I'm not sure if it's really an issue since I never had any overheating problems. I had always intended to try to drill some 1/8" holes between the bores on the center three pistons close to the edge of the block. Then I was going to transfer those holes to the head. Google "steam holes 400 SBC" to get an idea of what I had in mind.

Chevy holes are toward the inside of the block; I was going to put them further out.

Again, not sure it is really an issue.

Are the cylinders in the Ford 200 or 250 blocks siamesed, thats the only reason Chevy put the steam holes in the decks of only the 400 SBC, they were. None of the other SBC blocks had them because the block castings allowed full water circulation around the cylinders, so unless the cylinders are siamesed, the steam holes are likely to not be needed.

I see, I thought there might be a flow issue after blocking that many cooling passages in the head, but if there isn't and issue then that is one less thing to worry about! My next mission is to get a head gasket to try and begin prepping the block. Im going to practice on my spare block before trying it on the block the head will actually go on to see what the learning curve is like.

I wasn't really thinking about steam like the chevy 400 issue, but if you look at the crossflow head the water passages on the outer right side correspond to the area around the exhaust ports and valves. I'm not sure, but there may be a need to introduce additional coolant flow in those areas to help move some of that heat. The 400 SBC was just an example of how you might be able to tap the coolant and move it into the head around those points.