The usual gearing of a 6 cyl 5 speed is 3:07. Although with a factory towing package a lower gearing might have been installed.
The 3:07 gear with the 26/27 inch tires would have the best gas milage from the factory. However evey increase in tire size would slow performance and lower the milage.
I'd be for a 4:11 with those tires you are after.
As the tire size increases it will take a few more rpm to turn them so if your hiway rpm is now 2100 you may want 2500 with the taller tires.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

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