Top picure is of a standard vacuumpump for 6.2 in trucks, Van,s and 6.5 had it mount in front of the engine, belt driven. next picure is of the Ess sensor.
Hi, if your engine have the vacuumpump with ESS sensor on top? you can use this for a rpm-signal with a diy circiut. One circuit is with a transistor and one with Lm393 IC.