@chryslercruiser
Determining the best Power timing for a street car is by testing how long it takes to cover a certain distance, with not enough timing, and then repeating the test with an additional 2 degree. Repeat until the car slows down, then subtract 2 degrees.
This test must be run in just one gear.
The tires must not spin.
At the start of the test, the rpm has to be high enough that that the mechanical advance is all in.
At the end of the test, the rpm must be at or near the cam's Powerpeak but not much higher than 5 to 10 %.
This usually requires the use of Second gear. but
Depending on your rear gears, and cam, this could put you well into speeding territory, so you may have to attempt the test in first gear. but if the tires spin when you lay into it, you'll have to increase your speed until the tires no longer spin.
Say by 3500rpm in First gear, your combo will no longer break the tires loose. and say you have 3.23 gears. Thus 3500 will be about 32 mph.
And say your cam Power peaks at 4500 rpm, and plus 500 gets you ~45 mph.
So run your test from 32 mph to 45 mph, on a flat level no-traffic road. Mark your speed-O at 32 and 45..
Get a helper, with a stop-watch, in the back seat, looking over your shoulder, watching the speedo needle to start/stop the timer. YOU, concentrate on the road.
What yur gonna do is go hammer down at around 30 mph, so that by 32, the carb has settled down, and the engine is in max-effort mode. And when the Speed-o needle hits 45, your helper stops the watch, and you get an ET. write it down. turn around and go back to the starting point.
Add your two degrees and repeat. As you get closer to perfect, you may have to run multiple runs, at the same timing to generate an average ET.
With a V8 car, this test works better in SECOND gear, but the speeds will be excessive. I'm not gonna pay your speeding tickets.
But, you don't have to run all the way to 5500 or whatever. If you have so much power to weight ratio, that it only takes 2 seconds to complete the test in Second, it's gonna get harder with each run, to get an accurate ET. Thus you will be tempted to do the test in Third gear, in the which, wind-resistance will slow the rate of acceleration down, making it easier to be accurate.
If you get pulled over at 5000rpm =112 mph, do not mention my name.
If at any time you hear detonation, STOP the test! I ain't buying you new pistons either.
Be safe.
BTW, my helper was an accelerometer.
Like the GTECH-Pro SS.
Mine, not a Gtech, came out a year or two earlier and required a magnet to be installed on the driveshaft, and a pick-up installed to generate and send the pulses to a small ECU mounted in a tachometer-like housing. By inputting the weight of the vehicle, this device was able to generate a graph of the engine horsepower at each 100/ 200rpm (I forget). From the hard data, I could see the power increase with each timing increase. and when the power plateaued, I discontinued the test.
Then I went back and without increasing the Power Timing; by using a two-stage timing curve, I was able to increase the timing below 3500, and picked up some torque down there, using the same tool and test procedure.
The GTECH does the same, and by using GPS, it does not require the installation of the Driveshaft counter. But it costs a lot more.
No, I do not recall the name of my unit. Wait it just came to me; DYNO-RAD.
