my dart left me stranded

Don't feel too bad, when I first got my adjustable rockers I did the same thing. I landed up putting the old stuff back on and then just did one side and waited a few days till I did the other. I think you need to wait a few mins. for the lifter to come all the way up and once you set it leave it alone. After a few more mins. the pushrod will feel loose again but its ok.

As far as the MSD box, I have hear of them going bad but I must be luckly cause my 6 box lasted 8 years and was still working ok when I got my 7al and thats fine also. I do know there is other brands out there.