The Stovebolt Site Forums The Shop Area Engine Shop why not crossflow head?

Chevy, GM, AMC, Ford, International all made straight sixes with same side exhaust & intake for many many years.

There are many 'free lunch' performance advantages to a cross-flow head that they missed out on. Flow efficiency, high RPM, better combustion chamber shape.

It's not as if these effects weren't known at the time. ie. Wayne heads

So why did everyone forgo the cross flowing heads?

All the major manufacturers subscribed to the "baby chick" model of building millions of engines- - - -"CHEEP-CHEEP-CHEEP". Their aim was to make an inexpensive, reliable, long-lasting engine that met the needs of the majority of their customers. They left the exotic high performance head designs to people with more money than brains.
Jerry

I think there are just two choices with a Stovebolt engine: run them exactly as produced or replace them. With one of the worlds worst (for performance) head, intake, and bottom end designs trying to hot rod them is like topping a cow pie with whip cream---might look appealing but if you dip into one they are still excrement. Ford and Chrysler made I6 12 port heads and Ford made bottom ends with 7 main bearings nearly 60 years ago. Models of some Aussie 250ci Fords came from the factory with 12 port cross flow heads and yes, they run strong. Never could fathom why ones wanting to hot rod an I6 didn't just use a 240 or 300 Ford in their Stovebolt truck. If one feels they MUST have an all Chevy ride then the 2002-2009 Trailblazer has the Atlas I6 which has a crossflow head and makes more than 1hp per cubic inch stock; 275hp out of 257ci. With some rodding one can be over 500hp. Been waiting for someone (hint, hint HRL) to make a "dumb" Atlas with carb and distributor so pliers and screwdriver bolt owners would feel comfortable with them. Believe there is a market for such and engines are cheap and plentiful in the salvage yards now.

I believe it.
It would be interesting to know how it saved $ to build exhaust and intake on the same side?
Offhand it seems more simple to make independent intake & exhaust manifolds for a cross flow engine? Was all the sacrifice just so that they could use the exhaust as an intake heater? Did cam in block vs OHC also save money?

Or, was this a case of good enough being the enemy of better? An American automotive tragedy?...

In an alternate America:

Where in-lines rule the roost. Exotic V8 designs are left for people with more money than brains.

The 250 comes in two versions.
Economy SOHC, and performance DOHC. Economy single cam with traditional iron head used in trucks & common sedans but the coveted double cam version used in vette's and camaros comes with a cast aluminum head.

This vertical tower of power is worshiped as the most legendary tuner engine of all time.
Common among daily drivers, this is known as a million mile engine when properly maintained in stock form and is well loved for it's versatile power band.
The Chevy design really shines in the hands of hot-rodders, the 4 valve (per cyl) aluminum head with solid iron short block & 7 main bearings, is known to easily hold 30lbs boost, 1000hp & 8000rpm on stock internals while still maintaining street reliability!

Alas, it was never to be. America became the land of the V8, and the title of 'Most Legendary Tuner Engine' goes to JZ and RB engines from Toyota and Nissan. According to the internet (and Fast & Furious movies).

An excruciating, yet accurate description!
I'm in the process of applying some whip cream myself... will try not to taste more than the surface, yuck! Live and learn i guess.

The Atlas engine idea sounds intriguing. Maybe someone will quit their day job to sell sell carb adapters & accessories for it!

Why not L6?
Engine length (almost) prohibits dual use in RWD + AWD/FWD.
Engine size always has 33% longer stroke (and proportionate connecting rod length) for same displacement and bore pitch.
Long stroke: tall deck = hood clearance problem (292 or Atlas in small car) + higher COG than V engine.
L6 block, crank, and head are weaker in torsion (bending) than V engine.

W/r/t "bottom end design"
4 main bearings with staged sizes is exactly the same as almost any other L6 engine in the same period. Name a 7 bearing L6 before 1960?

W/r/t "head design"
That's the one Mercedes 230 SL etc. used into the 1960s...

I have an aluminum 12 port cross flow head being machined now from New Zealand for my 292. It was 10 years in R&D. It will cost less than 2 high performance V8 heads. Also the I6 lasts a long time between rebuilds due largely to the fact that you are shifting at 3500-3800 rpm's vs twice that in V8's. I know of a guy that has 8 seasons on his 292 @ 1000 HP without a rebuild. I will be keeping mine under 800 HP or so in race mode and 550 HP in street mode. They sound more like an airplane than a car. Expensive, yes. Trump expensive no. Super cool absolutely! More money than brains, that's a matter of priorities. I have no wife, kids or dept and have worked hard my whole life. So if I have 90K in my entire build so what. Have you priced new trucks lately? Which one do you think will be worth more in 10 years. By some peoples standards I have a lot of money but I didn't make it by being stupid. Just my $.02 worth. Thank you for your time.

Now if a 12 port, crossflow head for my 503 were available, that would be something.

Ed

At least we're not throwing our money away by doing something stupid- - - - -like playing golf! If I get a good hit on the ball, isn't somebody else supposed to chase it?

Evan, the Atlas "dumb" engine project is still in the works, just on temporary hiatus while I work on building a 260+ cubic inch "216" engine with full pressure oiling and a leak-proof rear oil seal. I'm also considering taking that project on the road to car shows and swap meets once the bugs are worked out, with a portable dyno on a trailer. Would a 150 HP engine that looks identical to a 216 have a market with "purists" who want an original-looking engine?
Jerry

Mick53, are you going to share your head technology when you get it worked out?

Ed

Major reasons why not make an aftermarket cross flow head for a siamese design?
Needs:
1. new intake manifold (handicap the design to continue use of original siamese exhaust positions)
2. new exhaust manifold (continue original siamese intake positions)
3. needs both

Successful new head requires:
1. Uses existing bolt locations (perhaps with longer bolts)
2. Rockers? Maybe, depends on the chamber shape etc.
3. Oil supply & drain
4. Water circulation
5. Cam - this is a very big $$$ deal. You can't use the original cam (or any regrinds etc.) unless the lobe positions match the new head. For stovebolt and Gen-3 (250, 292):

E I I E E I I E E I I E

Normally, 2 exhaust valve are never adjacent due to temperature problems.
By comparison, a slant 6 is:

E I E I E I I E I E I E

Yes I share everything I can. Since this is the first one I am not sure what I can say at this time but we'll see how it works out. It will be available in the US. Most of my parts cost so much because I have to pay their engineering charges. The good news on things like my crank, damper and other things they will be much cheaper for the next guy because the engineering has been paid for. They want people to know these parts are now available. We have discussed this. Thank you.

For any interested there are several offerings to help with a 4200 Vortec or "Atlas" engine transplant. The man that goes by the handle "efi-diy" on the Stovebolt site has a rear sump pan, bellhousing adapter for Atlas to 63 and up Chevy, and a standard trans flywheel. There is nothing wrong with a crank trigger ignition so that leaves mainly a non computer induction system. If a carb manifold comes out for one I will use a FiTech throttle body on it since they are self contained and self tuning plus I've had good luck with them. FiTech is now offering a two barrel tbi for inline 4's and 6's.

Do you still get the intake air cooling effect with tbi that you get with carbs with a blower?

Wherever any liquid (gas, alcohol, water) is introduced into the airstream will have evaporative cooling.
A "dry" blower case and manifold plenum (injectors inside the intake runner or port) won't.