I've been working on my Shoebox for the past 2 months and driving it daily. Has a great running 239 in it with the 3 speed and stock rear. I drive it on the freeway about 12 miles everyday. My questions are, What is a safe RPM range to take it to in 3rd? And what are the gear size in the rear end? I've searched and couldn't find anything from the HAMB or google. Thank you!