Originally Posted by cobalt327
You need to - like I did- test this w/a vacuum pump equipped w/a gage. I stand by my previous statements.
I had a chance to test an OEM(non adjustable)type vacuum can last night on the bench. The starting position of the connecting rod does effect the start point of the movement. Pic one shows the rod against the vice grip jaws at about 4"hg this is just below the start point,the rod has not moved yet. Pic 2 shows the rod starting to pull away or move at approx 4.5" hg. I then clamped the vice grip 1/8" closer to the can simulating what the crane plate would do if installed on the back side of the rod as I suggested. Pic three shows the rod now starts to move at 7.5"hg so that is 3" hg difference. I then tested my HEI with an adjustable can same thing. In both cases the plate does effect the starting point in relation to the vacuum applied.