I have had no issues with leaving it as it is. You can change the values to the correct ones, but I saw no difference between stock and 35" tires on a customer's truck when the proper (or improper) values were used.
You can make up for the taller tires really easily by just shifting the entire shift schedule up by 2-3 MPH in each gear range. These trucks don't use the PCM for speedometer calibration anyway so it's not really that important.
The 99-up Super Duty trucks are more dependent on these two parameters though.
__________________
Tuning, PCM flashing, and burning chips for 7.3s since 2008. Repairing all aspects of 7.3L Powerstrokes for 25 years.
Eight 7.3L PSDs in the driveway including a 1994 Crown Vic and 1973 F100/2002 F350. Looking for the next victim.
|