After reading through some posts here, I bought a durlast 49-DL to replace an optima that's been giving me some problems the last couple of weeks. The optima was install by a previous owner a couple years back.

The duralast is much bigger than the optima that it replaced. I don't know what was stock and what was not, but the optima was sitting on a foam pad (about 3/8 inch thick). There was also another foam pad between the mounting bracket and top of the battery(same material). I suppose this allowed a nice snug fit. I managed to get the new battery in place(on top of this foam pad), but the mounting aluminum bracket is a pain was a total pain in the ass to get attached(particularly to the end at the top of the battery. Now let me get to the problems/questions.

1) nearly impossible to get the bracket installed with foam pad (are they supposed to be there, or a mod that the PO used to get the optima to fit better?).
2) the battery is taller than the optima and I can't get anything to hold the nut at the top end of the mounting bracket while I tighten the screw-- the gap between the battery and the metal that the bracket mounts to on the seat frame is too small (maybe the foam pad the battery is sitting on is causing this problem).
3) When the bracket is installed its interfering (squeezing) the vent tube. The vent port sits behind the bracket. I don't think its compressed enough to prevent flow, but its hard to tell.