The salesmen/kid at parts counter, will tell you which one........I have a Red Top 950 cold cranking amps. I switch it between my 83 jeep j10 in the winter.
Be ready to spend about $140 on it....!!!!! worth it though
Dunno which size a "34" is I thought they where all the optimas came in one size but dunno. My car has a yellow top in it (soon to be in the trunk) and my freinds GT has a redtop both fit in the stock tray. Mine doesn't have a tiedown on it but his redtop fit with a stock tiedown.
I am the friend he was talking about, and I have a 75/35 series redtop in my car. fits great. Stock bracket works, just grab the mounting tabs from a larger sized battery and it will fit perfect. Just look it will be hanging on a different optima, I wanna say they are either grey or black.
theres two sizes of red top optimas, the small one fits without mod, and the big one fits if you modify the battery tray just a little. i got the bigger one because its stronger and i figured it wouldnt hurt with an amp in the trunk.