I installed an Optima yellow-top in my 1989 328 GTS this spring, and it's been just fine. I measured the old battery and found the yellow-top was identical to what was already in there. I liked the deep-cycle feature since I only drive my car every few weeks (except for USGP weekend, when I put ~500 miles on it). It has universal side terminal / top post connections. My car uses the top post connections. The battery gets held down by a clamp on the lower lip of the battery. I paid ~$145 at Auto Zone. The only problem I had was the arc welding job I did when swinging the wrench to tighten one of the cables. Oops! Thank goodness for the deep-cycle feature! (Glad the wrench didn't weld to my wedding ring.) Between starts, I keep the battery charged with a NAPA battery tender. No problems.
Spasso and DGS, yeah, it came with a red plastic adaptor. It certainly prevents forward-, backward-, and probably to a certain degree lateral displacement. As I mentioned, the 75/35 is shorter lengthwise (compared to the 34/78). There is only one hold-down clamp; it's the one you mentioned (see photo). The orange top apparently is not available anymore. Henry, I saw a 34/78 Red at Sears (STL) - their last one -for $139.99. I would have preferred the latter but I have already gotten mine. But you're right, either will work fine. Just to make it interesting here a photo of mine. Only a portion of the plastic adaptor can be seen at the bottom. Image Unavailable, Please Login
Bought this battery maintainer (1.5 amps w/ "float" mode, $30) at Sears. Was going to order what Dave recommended but the price went up to $52 in 2 days. Image Unavailable, Please Login
I spliced the battery end of the maintainer to this polarized 10-amp Radio Shack adaptor. (Thanks again Dave for the recommendation). Image Unavailable, Please Login
That looks like a nice unit and great price! UL listed no less... compared to the "ETL" listing of the Deltan Battery Tender Plus. Not sure the difference, but have always had more faith in UL and CSA's reputation. Dave
