Super Charged Slant Six

and the problem your having is that your looking at the head as cast... when i look at it i see some ports that dont belong in a 6 head!

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Doesn't matter how big you make the ports; they all end at valves that are too small to effectively feed much more than 200 cubic inches, if that.

The factory killed all chances of a large displacement /6 ever breathing very well, normally aspirated, when they chose a 4" bore center spacing, which dictates really small-diameter valves, regardless of the port sizes.

The stock cylinder displacement (which ALREADY has a stroke that's pretty much at the max for work above 7,000 rpm, due to egregious piston speed,) is about 39 cubic inches per cylinder, which purely by chance, happens to be almost exactly the displacement of a 302" small block Chevy V8 (Z-28 variety.) If you'd been paying attention, back in 1967, when that engine first saw the light of day, you'd have been aware that it was a particularly well-breathing engine, with several good things about its design that gave it an edge. It had a 4" bore, and a 3" stroke, giving it room for 2.02" intake valves and 1.6" exhaust valves.

The slant 6, which is trying to feed (in stock form) almost the same displacement per cylinder, when we fit it with OVERSIZE valves (as large as most guys can get into the combustion chamber) that are 1.74" on the intake, and 1.5" exhaust.

The stock Chevy intake (2.02") is 15 percent larger in diameter than the maxed-out /6 valve, while the 1.6" stock Chevy exhaust valve is 6-percent bigger-diameter than the Mopar, that is the "oversize" unit.

I am sure that there are some one-off Mopar /6 heads out there that have larger valves that these, due to offset guides, but the combustion chamber wall's proximity will probably shroud the edge of the valve to the extent that the gains in overall size may well be cancelled out by the difficulty in getting air to flow around the periphery of the valve, due to the closeness, with the increased size.

In short, getting sufficient air flow in and out of a large displacement /6 (300 cid?) would require changing the bore/stroke ratio to something more amenable to large-diameter valves, and/or shortening the stroke to something more in the area of a 170, so that it could wind like that Chevy, and if you do that, there goes your displacement.

It's a physics problem that seems (to me, anyway) not to have an answer, beyond forced induction.

The good part is, because of their incredibly strong infrastructure (due to their origin as an aluminum engine,) that (forced induction) makes all kinds of sense on this engine.

My 2-cents..