305 vs. 350 TPI 730 EPROMs

["TRAX" <trax@frederickmd.com>]

Why is it that the 305 has significantly more advance in the spark tables
compared to the 350 (1991 F-Body 730 ECM)?  Could the use of the 305 spark
tables in a PROM for a 350 produce excessive knock retard?

I am asking because I have a friend who is experiencing significant knock
retard in his 1991 Z-28 305TPI automatic.  This car has a transplanted 350
(w/ 350 knock sensor).  Although the car has a custom PROM in order to work
with his 19lb injectors, I have noted that the spark tables are basically
the 305 tables.  Furthermore, he is still running the ESC filter that is
attached to the 305 MemCal.  Is the ESC filter on the 305 MemCal tuned for
the 305 engine?  Would he need to be running an ESC filter that was designed
for a 350?  As a side note ... this car is not in need of fuel.  The O2
values at WOT show > 920 mV across the board.  In fact - the car is actually
running rich right now.

Tim

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