454 Timing Question Using TunerPro

[Biglar]

Just a question regarding using TunerPro to set initial timing. Have a 1995 Chev G30 with 454 (7.4L). The crankshaft timing marks are impossible to see and my old timing light isn't working all that good. With the spark advance wire disconnected for distributor (per data plate instructions) can I use the spark advance degrees indicator within TunerPro to adjust my timing?

Also secondary question for those 454 expects, found two crankshaft timing plates for the ignition timing, one near bottom of engine and the other just near the top, which one does one use and why is there two to begin with?

[EagleMark]

Not sure about the 2 timing plates?

But no you can not set base timing with TunerPro. Base timing needs to be physically set with timing light at timing marks by disconneting EST bypass wire, then set timing by moving distributor. 454 are usually 3.9 degrees and small blocks are set to 0.

[Biglar]

Thanks for the answer and sort of knew that was going to be the answer, but I was once told 'the only stupid question is the one not asked'

Oh well off the get a better timing light.
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[grampadirt]

Hope I'm not too late....

I couldn't time my old '79 P30 motorhome either but just by chance one day I was looking around under the engine and found the lower timing tab.I'm guessing it's used because it's impossible to even see the front of the engine(454)to access the normal tab.That timing tab is for the next firing cylinder which is #8,connect your light normally except put the inductive clamp on the #8 wire and set the timing per spec.I have a short video on YT if you'd like to see it.