35" tires affecting speedometer, odometer too?

[jordanblea]

Hey guys I posted this question on the 67-72 pickup trucks board but figure the blazer/jimmy guys might be more familiar with a lifted truck question lol.
Hey guys not sure if this is a stupid question or not. I have been keeping a log of how many miles I cover vs how much gas I buy to try and get a ballpark number on mpgs. My question is this, with 35" tires my speedometer is off, says I'm going 50 when im going 61-62 mph, which is ok I can deal with that, but will that also throw off what my odometer is reading? Like if it says I went 40 miles, but really went 50? That'd be nice....Anyways, thanks!