Hey, I just posted this to the AMC-list. It directly answers "why destroke" ... I'm using SCDynoSim software for the numbers. It's not that the numbers are exact, but that they show trend and curves, and let you do what-ifs on valve size, turbo A/R, etc.
OK, I've been picking at this, I think I worked out the big chunks of how the Navarro six was set up. It's 5.95" bore by 3.00" stroke, for 182ci, from a worked-over 199ci.
I calculate 520hp at 5800 rpm, a broad flat torque peak of 500 ft/lbs from 3500 - 5500 rpm, with a Garrett turbo, .50 A/R, 3.1" turbine, 25 lbs boost. It's in the green for surge, overspeed and choke.
I have two TE-06 turbos with A/Rs around .47, plus a T04 same A/R. I plugged in small tube headers, open exhaust. And the factory stock cam! I kept getting crazy numbers when I tried the specs from the Winfield cam. I assumed that something like that was installed, but maybe that cam was in a box, on a shelf, for a reason. I really have no idea what was in the motor, but the software made sense when I used stock numbers (actually, a 195.6OHV cam as that's what I had entered and saved, but it's pretty much the same as the 199/232). I wasted a lot of time trying to fit that radical cam into the equation.
It's gotta ping the whole time though. Probably why the monster cylinder walls, crazy exhaust valve, double-O-ring head and block, etc. It looks like Navarro upped bottom end oil supply, but the valve junk in the head was totally stock.
OK so no one today would make a 500hp 199ci six (though it would be most cool at the track). But if you took a dead-stock 199 with .030 over pistons, ran 8 lbs of boost, and $$$ your way to 6000 rpm, you'd have 300 ft/lbs torque from 3500 - 5000, and 275hp around 5500 rpm. (It's the same shape curves as the stock 199, just taller :-)
That short stroke is the key -- the 232 gains a lot of torque, but loses 1000 rpm and 20 hp. The 258 is even worse, lots of torque, but HP peak moves down to 4000.
A hot 199 would be a fun, unique, and relatively cheap motor. Light too, and uses parts that no one wants (Rambler Mentality).
So I think this is what I'm gonna do with the fancy Navarro head.
