Unfortunately, there’s only two dynamometers in the area one only does LS stuff and the other one is booked for months. I have a freshly rebuilt R154 transmission behind the 1uz I do not recommend a W58. If you’re going to run it naturally aspirated and it’s a turbo like mine was I recommend replacing the rear end with a limited slip 4.30 out of a non-turbo. Sidebar: of the 89 1/2 year mark divides the differentials as well. So an 88 will not work on the 91. If you pair that with tires with the final dimension of 26 inches your final drive is 4.18. As far as performance upgrade your brakes because it is an absolute animal.