[V8Vairs] Corsa tach-V8?

[NicolCS at aol.com]

Engineering specs and Craig in one corner and...
Crown Engineering and Seth in the other.  
Who will come out a winner tonight?
 
I (Craig) rigged a Corsa tach on my test bench.
 
Test target rpms
500 / 2000 / 4000  (6cyl. 25/100/200 hz, 8 cyl. 33/133/267hz)
 
Baseline  6 cyl. readings (41 year old GM calibration)
550 / 2175 / 4200   or + 50 / + 175 / + 200
 
After recal.
575 / 2000 / 3900   + 75 / correct / -100
 
Adjust according to Crown / Seth @ 2000 rpm using V8 frequency
550 / 2000 / 3900   + 50 / correct / -100
 
So, despite the scribes at AC Delco's assertions...
 
Crown and Seth win!  Calibration using only the adjustable pot @ 2000  rpm 
yields a
tach reading that's just as accurate as a correctly calibrated factory  tach.
 
Ta Da!
Seth gets the prize and Craig, well, Craig says GO Seth!