some cranks have a "end" that is longer or shorter than others,pull the trans. and measure the distance (with flywheel on) from the face of the flywheel [tranny side] to the the back of the block. Then put the converter on the transmission. VERY IMPORTANT, make sure the converter is all the way on the snout. Then measure the distance from the transmission bell housing to one of the mounting pads on the converter. There should be only 1/8 of on inch of play difference. This 1/8" has to be longer than on the transmission side than the engine side. You might have to have the converter machined for the difference like I did. Also remember if you have to take material off the converter mounting pads you must also remove the same amount off the snout of the converter (the end that fits in the crankshaft or crankshaft spacer. You can also use a different crankshaft spacer to make up the difference. I milled the converter in my case