Quote: Thanks 360View! Some good reading there. The descriptions there seem to me like they want a cam ground with wide lobe seperation and then retarding it to keep the exhaust opening/closeing the same, is that how it sounds to you? The late intake closeing will definately bleed some preasure back in the intake. I would guess this forward-backward motion of the mixture around the valve would help atomize the fuel more also and provide some increase in efficency.
I doubt this backflow will help fuel atomization. I bet it makes it really difficult to tune a carb properly. Have you ever seen how a 2 stroke with a partually plugged exhaust will spit fuel out of the carb throat even at idle? This happens even when the exhaust is free flowing enough for the engine to run at 50% power. I think fuel injection is the only way to go if you want to use the Atkinson cycle. Don't discount lean cruise either, it can't really be used by the OE due to the increase in NO emissions when running lean. It will significantly increase fuel mileage. The GM tbi software tweaked for lean cruise is readily available for free. GM tbi should be sufficient for your engine and is the cheapest way to put fuel injection on a engine. However the learning curve is much longer than with aftermarket systems.
Don't discount deep gear ratios, the Corvette gets really good fuel economy on the freeway if you can keep your foot out of it. The 2008 6 speed gets 26 mpg EPA highway fuel economy. A significant factor is really low rpm in high gear. I have a a body 8 1/4 with 2.45 gears from 1975. I have heard that some Diplomats and Fifth Avenues had 2.25 gears.
People tune carbs all the time with late intake valve closeing all the time, thats how most high performance motors are running any how, and they have a bunch of dilution to deal with from overlap and they have early ex opening to reduce expansion time so I don't think carb tuneing wil be that big of a deal unless I go extremely wild with this thing.
I am keeping the 8.75 for one day putting a big hp motor in it and my 2.76 is the highest gear I can find for it. I will also be keeping the TTI headers. If someone wants to donate a 4spd set up for this car I would prefer that but right now I don't have one so I can't. I am going to develop this motor in my car and when I find something suitable for the wife it will ultimately go in that, hopefully a 4dr dart or a nice station wagon.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
