I am currently building my '72 Blazer. I am putting 4" springs front and rear. I am puttin' the throttled body 350, 700R4 and NP208 from my '91 Blazer into the '72 blazer. I have everything squared away but I am stuck on the speedometer. My '91 is electronic and my '72 is mechanical. I have built a few truck in the past 10 years, but this is my first time putting a fuel injected engine in an older mechanical fueled vehicle. Does anybody know of a way around my speedometer problem that wont cost me 300.00 or more dollars?