I know you checked things around the area of the pcm but it sure sounds like
there may be a bad connection since things have been disturbed a good bit
all around that area lately.
I'd look at the service port since he pulled the old chip out to see if anything
looks out of line.
You kinda need to keep WOT conditions separated from cruising around town.
If you are at a light to medium load .....
a mix greater than 14.7 is not uncommon.
At WOT ....... a mix of low 12's would most likely be a bit fat
As for the dizzy being at 14
You really can't tell a whole lot by that kinda thing
You don't have a clue about what is going on with your spark unless you know
how he is making his adjustments
See ... here is the deal with spark on SBF's since their inception
Well ... first ... lets just cover the basics
You got total amount of spark
Then you got how it is controlled
Now ... back to SBF's
They've always produced max WOT power at 36 give or take a few
and
You'll always pick up power if you get it all in quicker
Now ... having said those two things ... lets talk about our pcm 94-95 Stangs
The amount and rate of advance is controlled by the spark tables in the pcm
If you don't have pcm access ... you can't obtain both of those objectives
Allow me to post up an unmodified spark table from a 94-95 Cobra
First ... A bit of basic info for those who've never seen such a table
On the left side you see load with bottom idle and top WOT
Across the top you see the rpm
All values are as they are with the fact the dizzy is set at OEM value of 10
What you basically would do is ..........
Increase the value in the top row (WOT) to around 36
and
Have it come in quicker by being all in by 2500 or there abouts
Now ... look at what happens if you don't have pcm access
To obtain your best WOT performance you want 36
sooooo
You have to twist the dizzy an additional 10 to obtain the 36 total
That just won't be a possibility as the mid load values will be too high because
when you do the ... dizzy twist dance ... its a global kinda thing and its in effect
at all loads.
That much of an increase will wreak havoc with your mid load values
and
Most likely produce the dreaded ... ping thing
Of course ... it goes without saying .............
Twisting the dizzy will do nothing about the rate of advance as well
Summing up
In your case ... if he was only doing mechanical tuning
You would add 4 to
ALL values as he bumped the dizzy setting up by 4
Basic Stuff Really
Maybe some will find it helpful
Grady