RTz

Hi, Have you tried RuschMotorsports?... 503-668-6805 rt

Mike, I seriously doubt you offended anyone. If I remember your original post correctly, I got the impression what you're asking for isn't available (that I'm aware of). The closest thing to meet your needs would probably be a standalone engine managemnet system ie, Megasquirt, Wolf3d, etc. rt

Dont know if this helps... my records show 280-150-153's to be 236.5 cc @ 43.5psi rt

Jon/Paul, Sorry for the deley... burned up my keyboard last night (damn Vino ) Anyhow, not sure how useful this is but I'll tell you what I did and you can decide for yourself. I installed a VR sensor on the crank of my 510 (still L- powered). I also installed the matchbox style elec. dizzy. This sensor is also VR. I then took a two channel O-scope and data logged both VR's. Keep in mind that the dizzy still had mech. advance (also vacuum adv. but disconnected). In general, 80% of the time, they 'scattered' inside of 4 deg. The remaing 20% of the time, there were scatters between 4 deg. and 8. I didn't spend a lot of time with this so take this as general info. Afterwards, I machined a trigger wheel to fit the dizzy shaft and paired it with a Hall effect. This eliminated the Mech. and Vac. advance, so now were dealing with primarily gear slop. I re-tested and found them both to ramain plus or minus 1 deg. A pleasant suprise... I had expected worse. HTH, rt

To no one specifically, Just for clarification... I see a hint of interchangeably referring to wasted spark and dual post coils within this thread. They are not the same. You must use dual post in a wasted spark config. (or put both plugs in the same chamber). But individual coils, such as COP's can be run either sequentially or wasted. rt

Alex, I don't belive I have it backwards. This discussion pivots around the two plugs in series having opposite polarity. So, with one plug, you'd be correct, from ground strap to electrode. With the other plug, its from electrode to ground strap, as Braap's diagram is drawn in post 1 of this thread. HTH, rt

Braap, One thing I'd like to clarify... peak ignition demand is frequently at peak torque (depending on the application), not always peak RPM. Your last sentence said that but it was a little "hidden". rt

Alex, On the surface you're correct. However, take the typical single coil/distributor system and reverse the polarity on the coil and you will reduce the spark performance. Depending on the car, you may or may not notice a power drop, but you WILL likely notice a MPG drop. Its a subtle thing to be sure, but some folks are running some serious boost/RPM and, in my opinion, under those conditions, the benifits are tangible. I quote two gentleman citing roughly the same cause.... "The center electrode in a spark plug runs hotter than its grounded electrode. Since electrons can be striped off of a hot electrode more readily than off of a cold electrode, the center electrode is always made the negative electrode. The result of this choice is that the arc across the spark plug electrodes can be initiated at a slightly lower potential when the center electrode is the negative electrode. (In this manner, thermionic emission aids in the establishment of the initial discharge.) Best wishes, Carl Cederstrand" And... "Spark plugs are sensitive to polarity and they will not function as efficiently it the secondary coil voltage is of the wrong polarity. The reason for this sensitivity is as follows. The centre electrode has a higher temperature, normally, than the ground electrode so that more electrons will be released from the hotter metal surface of the centre electrode than from the ground electrode. If the centre electrode polarity is more negative than the ground electrode (which is connected to chassis) then the earth electrode will attract electrons from the centre electrode; but if the coil secondary voltage polarity is reversed, the voltage needed to cause electrons to pass from the earth to the centre electrode (i.e. to make the gap conductive) is increased. All the best -- John Harper" HTH, Ron

All, Isn't it the "smaller" of the two basic (modern) motors Chevy manufactures? rt