Tom, years ago I mildly hopped up a 196 in a 62 American convertible. I replaced the intake plate with one I fabricated to take 2 MG SU carbs. They were mounted to 90 degree elbows welded to the plate. Ran OK but I think the stock 2 bbl intake from the 138 horse engine ran as good. Offy used to make a manifold that used 2 stock 1 bbl carbs. This engine did respond well to a 2 inch exh pipe and free flowing muffler.
And Desktop Dyno software agrees with your reality! :-)
Yeah, the large mass and long stroke kinda limit it, and I can see the exhaust probably strangles it. I'm still running some old replacement rusty exhaust now, it'll fall off soon then I'll go big as I can with a good muffler, probably Summit like I did on my Hornet. Flow can't hurt!
Swapping in a 232/258 into a 196 car is a hassle. Did it in a 65 American.
Yeah, in the pre-64 Americans, the new six is 9" too long! That old Nash motor is SHORT!! Narrow too. Pretty much no choice in the matter.
My 63 Classic came with a 195.6 OHV aluminum, I stuck a
'70 232 in it, with a '64 crossmember, and redrilling the mounts 1" forward.
I would think a 196 with a turbo is the way to go. Forged crank and rods stock. Piston walls very thick. Could handle lots of boost and probably stay together. Mike
I wonder about head sealing. As you probably know this motor has a history of leaky heads and blown headgaskets. I'm willing to chalk most of that up to poor maintenance, they are all 45 years old at the newest. But there's not many headbolts, and they DO require retorquing.
But even 4 - 6 psi would make that sucker go! Even 150, never mind 170, hp in that tiny little car would be QUITE pleasant.