Best way to find out is...use the SOP meter...Before and after you remove the chip.
Get one of your buddies to ride along with you. Find a level stretch of road where you can do some testing. Watch for the wind speed and direction, it can have a definite impact on your test results.
Don't choose a speed range that will make you shift gears, the shift quality & speed will affect your results. Use 2nd or 3rd gear and do a run from 2000 RPM to 5800 RPM. Call out the RPM as it increases and have your buddy record it and the elapsed time. If you have one of those cheap digital watches like I do, a stop watch is built in.
Remove the chip, use a timing light to set the timing and give it a try.
Setting the timing:
Paint the mark on the harmonic balancer with paint -choose 10 degrees BTC or 14 degrees BTC or something else if you have NO2 or other power adder. I try to paint TDC red, 10 degrees BTC white and 14 degrees BTC blue.
10 degrees BTC is towards the drivers side marks.
Note: setting the timing beyond the 10 degree mark will give you a little more low speed acceleration.
BUT you will need to run 93 octane to avoid pinging and engine damage. Pinging is very hard to hear at full throttle, so it could be present and you would not hear it.
Simplified diagram of what it looks like. Not all the marks are shown for ease of viewing.
ATC ' ' ' ' ' ' ' ' ' '!' ' ' ' ' ' ' ' ' ' BTC
---------------- >
Direction of Rotation as viewed standing in front of the engine.
The ' is 2 degrees.
The ! is TDC
The
' is 10 degrees BTC
Set the timing 5 marks BTC. Or if you prefer, 5 marks towards the driver's side to get 10 degrees.
To get 14 degrees, set it 7 marks BTC. Or if you prefer, 7 marks towards the driver's side to get 14 degrees.
The paint marks you make are your friends if you do it correctly. They are much easier to see that the marks machined into the harmonic balancer hub.
At this point hook up all the wires, get out the timing light. Connect timing light up to battery & #1 spark plug. Then start the engine.
Remove the SPOUT connector (do a search if you want a picture of the SPOUT connector) It is the 2 pin rectangular plug on the distributor wiring harness. Only the EFI Mustang engines have a SPOUT. If yours is not EFI, check for a SPOUT: if you don’t find one, skip any instructions regarding the SPOUT
Warning: there are only two places the SPOUT should be when you time the engine. The first place is in your pocket while you are setting the timing and the second is back in the harness when you finish. The little bugger is too easy to lose and too hard to find a replacement.
Start engine, loosen distributor hold down with a 1/2" universal socket. Shine the timing light on the marks and turn the distributor until the mark lines up with the edge of the timing pointer. Tighten down the distributor hold down bolt, Replace the SPOUT connector and you are done.
The HO firing order is 1-3-7-2-6-5-4-8.
Non HO firing order is 1-5-4-2-6-3-7-8
As for your idle/stall problems, there may be something other that a cam causing them.
You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the
Surging Idle Checklist. Over 50 different people contributed information to it. The
first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

:
It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 125,000 hits, which indicates it does help fix idle problems quickly and inexpensively.