Re: [AMC-List] performance cam for 196 ohv

["Swygert, Francis G MSgt 436 CES/CECM" <Francis.Swygert3@xxxxxxxxxxxx>]

I had the cam cut for a 196 OHV -- 20* more duration, 0.10" more lift.
It didn't affect bottom end at all, gave an added boost of ~20 hp in the
mid range (where it was most needed). The car actually had a bit of
passing and pulling power while cruising! I also had a 2" exhaust system
with 16" generic turbo muffler and an open air filter, which helped the
engine breathe better than the stock 1-1/4" tail pipe. I retained the
1-7/8" head pipe (from engine to muffler) as it fit snugly inside a 2"
pipe and I didn't have to be concerned with having a pipe made to fit
the original manifold.

The cam is definitely different from a flat head cam. The bearings are
the same, so the cam would fit, but the lobe profiles are totally
different. Flat head lifters act directly on the lobes, the OHV has
1.6:1 rocker arms. The OHV cam wouldn't have close to enough lift for
the flat head. 

IIRC your car is a flat head/auto combo -- a red 61-63 two door wagon,
right? The turbo muffler isn't real loud, though noticeably louder than
the can't-hear-it-running stock muffler. Nash got 110 hp from the 196
L-head by using a 2V carb and glass pack muffler with resonator (to
eliminate the "bark" of a glass pack). A good 16" or longer generic
turbo muffler would be about the same. It's a little louder than stock,
but not really loud. You could use a generic replacement (non-turbo)
muffler w/2" in and 2" out and probably get about the same effect as a
turbo muffler. The tailpipe size is the real restriction. You can get a
2V to 1V adapter that works fine on the L-head, but that's probably not
needed. The L-head already has an open air filter, so no help there. 

If you don't want the mods obvious, I'd stick with the muffler/tailpipe
and a cam change. A modest increase in the cam won't affect heat that
much. Lift is limited by the height of the combustion chamber over the
valves. You need some clearance, and I don't know how much is there now.
Another 0.10" lift should be doable without machining the chambers for
additional clearance, but the only way to find out is to pull the head,
put a spot of clay on the valves, then reinstall the head with the old
gasket (and torque down at least 2/3 required torque) and turn the
engine at least one complete revolution. Then pull the head and measure
the thickness of the clay. You only have to measure one cylinder, of
course. Any company that produces cams for flat heads (even the Ford
V-8s) will know the limits for cutting a flat head cam as far as
overlap. Most cam companies will regrind a good used cam for you, it
just takes a few weeks. I had Lunati in TN cut mine. I just called and
told them I wanted a little more driving power, they suggested the
grind.

I don't think a modest amount of turbo boost (3-5 psi) would cause to
much of a heat problem. ALL flat head engines have a problem with heat
due to the exhaust passages in the head. Superchargers are used on Ford
flat head V-8s with no problems. I'd just stick an oil cooler on the oil
line between he filter and block (something small like a VW bug cooler
is enough) to help out a bit, and install a shroud on the fan -- maybe
the five blade fan used on AC equipped cars too. The L-head 196 has an
open four blade fan stock, so it won't take much to improve on that! 
 
Now where have you guys heard about bolting a turbo flange directly to
the L-head carb mount? ;>  I mentioned I'd like to do that a lng time
ago, with a 1V throttle body right between the head and turbo instead of
the carb. I think the hood is high enough on the American to do that. It
would be easy to drill the side of the block for injectors. I'd just use
four injectors since there are only four intake passages (two inner ones
are siamesed). I suppose I could use a sequential computer and have it
fire the two inner injectors twice for whatever cycle was needed. Or use
a TBI computer and injectors, but centrally mount the injectors in the
side of the instead of in the throttle body to keep height of the TB to
a minimum. Could use a "suck through" setup with a 1V TBI unit instead
of a carb though. A TBI unit would be a good alternative for the Navarro
carb setup, Tom.

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