I have seen some threads of guys saying that they burned up the bearings or screwed up their dist. gear on their new dist. Some said it was because the dist. gear was located wrong on the shaft putting a load on the bearings etc. Here is a tip that might help. Take the cap and rotor off your dist and put it down in the hole all the way. Hold down on the shaft where the rotor goes and lift up on the dist. housing. If the housing comes up a little, you will know that the dist gear is going all the way down to where it spins against the block. Now do the opposite: hold down on the housing and pull up on the center shaft. If it pulls up a little, then you know that you are not binding the bearings in the housing. This way you know everything is O.K. before you fire it up. Someone said that MSD was giving specs from the bottom of the dist gear up to the ledge on the housing and that those figures were wrong. I had a FRPP gear and it came with a paper with the specs of 4.031"-4.038". I checked my MSD dist and it was 4.035" and seems to be perfect in the block. Hope this helps someone!