Sure, they made a billion Slant 6's.
And yeah, they last forever.
But how many are still around?
Let's look at this for a second...
Y'all want to take the disposablest of the disposable (Cheap engine in cheap car that was out of fashion for 30+ years to most people), and have someone tool up to make a head to save a few pounds and flow a few CFM more on a motor that has a racing family of how many people, exactly? Dozens? Even worse, y'all want someone else to pony up the money to see if it'll pay off and make them a profit so they might be able to pay their people and try to keep doors open?
This ain't the R+D on an intake, either. This is R+D on a head, that's much more complex. There's no moving parts on an intake, rarely is there oil flow to layout, cooling passages (that matter much), etc, and they admittedly aren't cranking out the intakes hundreds of people want to fit thousands of motors still on the road and made into this millennium, as it is....
Those /6 engines didn't wear out, they were killed off. And they were killed off because nobody cared. There was no money in slant 6 cars when it came time to rob the doors, hoods, fenders, and transmissions for other, more desirable cars, and now the rarity is biting you square in the ace because you want a part for an engine that's known to last forever.
In other words, in that subset of people that still care for these engines (Make no mistake, I'm one of them), how many of them are going to replace a head just because they want to? Most people aren't going to replace it for the hell of it, y'know; they're going to replace it if they need to.
So you've got a small subset of people still running these, and a smaller subset that either needs a new head or is willing to swap one for the 'neat' factor (which is then generally noticed by even fewer people unless your billboard sticker says 'aluminum headed slant 6' instead of 'Hemi'), an even smaller subset of people competing with these engines, and then an even smaller subset of people within the other three that can afford the thing.
I spy every old car coming or going in my daily travels, and of those old cars, I haven't seen a slant 6 or, anything that might have had a slant 6 in it from the factory, in at least a couple years, and we have monthly car shows a block from my house!
I have literally seen a factory Hemi Charger Daytona on the street more than a Slant 6 in the last 5 years.
They might make 'em, but if I was in that business (and I've made repro parts for other industries and I got bit every time), I'd politely tell y'all to leave me alone and call the Aussies or New Zealanders.
If it's that easy, YOU pony up the bucks, and YOU design it, and YOU make it.
And make it a Hemi head while you're at it. I will do the solid modeling and blueprinting. I offer that right now. I charge $60/hour but I'll cut you guys a break if you're serious.
