Inliners International Forums General Discussion Hi Performance Cross Flow Head 250 292

Keep your fingers crossed. A newly designed cross flow head for the 250-292 Chevy motor is in the works.

It is being developed in New Zealand by a daring individual. Intake will be on driver side and exhaust on the passenger side. Intake flows will be around 250, not sure on the exh. A custom intake will need to be made, same for the exhaust.

Individual intake ports are used. The chambers will also be of a modern quench type design.

The head is in the final stages and should be cast soon.

Just putting this out to see what interest there is.

It sounds interesting. I guess as with everything interest will depend on price. We could save on shipping by having some of the multitude of Kiwis who go to Bonneville bring them along.

They actually will only be available through US distributors that you will buy from, so the shipping will be rolled into the cost from them. As soon as they do come available, the R&D will begin to see what, if anything needs to be tweaked before they are released to the public. Should be interesting to finally have a 21st century cylinder head for these engines.

:-)

Two suggestions (based onmy own experience w/ prototype crossflow heads):



Make the head such that a simple adapter plate can be used to mount existing U-flow manifolds so the user will not have to obtain another manifold. Same with exhaust side.

Make the head so it can be machined to flow A LOT more than 250 intake.

Will these new heads be iron or aluminum? With the low cost of sbc aluminum heads available why isn't the hybrid head more popular? Seems like reasonably straight forward deal other than plugging the block water holes. I am baseing this on Leo's build only.

This new head will be aluminum. Several reasons why the hybrid head isn't more popular is most racers have no interest in it, plus you don't end up with any better of a head than if you built a true brazed lump port head or a Kirby 12 port head. Also, you weaken the block too much by changing the bolt pattern to the head by redrilling into sections that don't have bolt bosses cast into the blocks deck surface. The later LS style V8 head would probably be a better choice because it comes much closer to using the existing bolt holes in the block than the early V8 heads do. Its also easier to make the head fit the block instead of trying to make the block fit the head. By the time your done, you just have too much money spent on doing a hybrid head compared to buying a head that already fits the block that doesn't require altering the block or head. I think the hybrid head was more of a "because he could" kinda' thing instead and just being different than thinking it actually was providing any real gains over other options that are available, and I think others see it as that and haven't tried to do it for themselves.

That sounds interesting, finally another aftermarket cyl head that sounds to be better than a siamesed head.

If it only flows 250 CFM @ 28 inches, that is not much better than a lump port siamesed head? although they will be individual ports, that's a plus.

The Ford aluminum aftermarket inline six head flows better than stock but it's not cross flow & you do not need to make your exhaust manifold? A stock one or header can be used?

What's the price of the Ford head,, $1800, I think that is a good price for an aftermarket cyl head.

MBHD

I was wrong about the flow. Initial testing shows 270 on intake and 200 on exh. With more to be had with details.

Using flanges to bolt a intake or exh will be light years ahead of clamping the parts on.

This would also be a cleaner head to bolt a turbo onto.

Yeah its 270 CFM right out of the box, unported. So it has a lot of room to grow and can accomodate the needs of the more serious performance enthusiast looking to go to the next level.

The stock Gen-3 L6 cam lobes for the siamese ports are:
E I I E E I I E E I I E
Is the new head the same, or will it require a billet cam?
What makes this interesting is that the Chrysler Australia "hemi" L6 motor has the same bore pitch as the Chevy (4.40"). If the valve positions for separate ports are:
E I E I E I E I E I E I
the Chrysler's Weber, etc. manifold would be an easy adaptation, they might even make the intake side match the Chrysler completely to avoid the problem entirely. But - a new cam would be $$$.
Here's a 4 bbl. Chrysler manifold

The costs of having the firing order changed on the new camshaft is not much more than the cost of an off the shelf camshaft. They might tack on a few extra bucks to call it a custom grind, but they all start out as round lobe blanks, and at they point can be made to accomodate any needs. A cam that has already be ground for one firing order cannot be reground for another firing order however. No need for billet unless you just wanted to use a roller cam.

they all start out as round lobe blanks
We disagree.

I guess it depends on who is making the blank. All the ones I have ever seen are all of the round lobe, unfinished variety. I'll post a pic I have done lately for a customer. Who are you meaning by "we", you've been here long enough to know that no one every agrees with you.

I'm REAL interested! I am willing to buy a bare machined head as I want to do some valve train mods anyway.

any word on this new head yet

Work is still being completed on the patterns at this time. It was discussed to try and have a few raw castings made by the end of this year, so we'll see how close they make the deadline.

Any more news/updates?

Looking to have some raw castings before the end of the year. Got a few emails in the last few weeks stating its still on schedule for that. So we'll see.

Do we have a ball park price?

Minimun $2000 ish will be my guess.

MBHD

Hard telling. I would hope it to be less than that. Plenty of variables, casting, shipping, machining ect.

Gotta love those Aussies. They do sick stuff with 6 cyls!

There aren't any Aussie's that have anything to do with this head, where did you get that idea.

No... but they do have other brands of very high tech crossflow heads in Australia. Aussies in general do not view inline sixes as red-headed stepchildren as do many American consumers.

No... but they do have other brands of very high tech crossflow heads in Australia. Aussies in general do not view inline sixes as red-headed stepchildren as do many American consumers. [/quote]

The Flyer speaks the truth here. Even in our own ranks are those who view the inline engine as a cute quaint leftover from another time. Tell that to the import tweekers whose turboed 4 cylinder inlines are the street racing terrors of the 21st century. Then look at what was offered in Australia in inline performance while we were drooling over cubic inches. We have to reverse engineer our inlines.

I'm waiting to see what intake and exhaust options are going to available for this new head. Them down under boys have engines that were designed for utilatarian use rather than speed like early Amercan engines, they have their share of V8's but the inline motors have the majority.

I believe this Toyota Inline Six has done pretty well on US soil. What do you think?

https://www.youtube.com/watch?v=sTaPp9vLYe0

Anyway, after a long period away from my 250 Chevy, I´m now coming back slowly.
Good to know that new heads are been thinked and, even better, about to be produced.
There is a myth here in Brazil that someone at Sissel was casting the 12ports again.
I still havent see any arround. But I´m just curious to see this new kiwi head!

You don't need a cross-flow head, either. The Nissan 240/260/280Z (RB26, etc. motors) do very nicely with 12 ports on 1 side.

There is a new 12 port head for the 6's and an 8 port for the 4's about to make a splash on the inline market real soon including intakes and are not Sissel's.

There is a new 12 port head for the 6's and an 8 port for the 4's about to make a splash on the inline market real soon including intakes and are not Sissel's.

Quit teasin'! Who? When? How much? This will definetly have an influence on my build.

I'll leave it up to the manufacturer to do an official release but if you liked the Duggan and Deppe parts for the 6's and 4's, you're going to like this stuff. My guess is by the first of the year, possibly Christmas. I'm also hoping to see the new crossflow head by then as well, this will be an interesting year for inliners.

So is this going to be a street able head or is this primarily for racing applications?

The 12 Port head will be available in both a solid race version and also a water jacketed version for street and racing as well. Along with it will be a mechanical fuel injection intake manifold and a single 4 BBL intake. A finned valve cover and also a 2 pc. timing cover and one piece timing cover w/fuel pump drive mounting are also available.

An 8 Port aluminum cylinder head for the 4 cylinder little brother of the 250/292 is also available along with an aluminum race block.

Now we all need a 4.250 bore siamesed block.

I'd be happy w/a 4.125" bore to take advantage of a larger valved better flowing cyl head.

To me no reason to go that big unless you just want a bigger engine, & that's cool also.


MBHD

And a 5" Crank!!

tlowe,

Now that Scott has come out of the closet, so to speak, would you care to share more on the crossflow head?

I've been out of the closet a long time. Just came out of the correct side.

Progress is still being made on the 12 port cross flow head. A slight water jacket addition had to be made. Hopefully the 1 st castings will be coming out soon!

It's hard to imagine a cleaner design like this did not come out long ago. A turbo system will have it perfect. Hot exhaust on one side, clean, cool fuel and intake on the other.