brg2290

I wish to replace the battery on my '78 SC. I believe an Optima Redtop would be a good choice, but I'm not sure what BCI Group number (see AJ-USA chart below) to go with. AJ-USA salesperson said go with the "34", but the "35" offers almost as much cold cranking amps, is ~6 lbs. lighter, and is less expensive. So, what BCI group are you Optima owners running, and does anyone see a reason not to go with the "35"? Thanks, Gary S.

BCI Group__CCA RC CA Voltage Warranty

25_________720 90 910 12 36
Notes:* Red Top, Starting, Auto Posts, L-9.5 in., W-6.8 in., H 7.6 in.,wt. 42 lb

34_________800 120 1000 12 36
Notes:* Red Top, Starting, Auto Posts, L-10 in., W-6.8 in., H 7.8 in.,wt. 37.9 lb

34R________800 120 1000 12 36
Notes:* Red Top, Starting, Auto Posts, L-10 in., W-6.8 in., H 7.8 in.,wt. 37.9 lb

3478_______800 120 1000 12 36
Notes:* Red Top, Starting, Dual Top Posts, L-10 in., W-6.8 in., H-7.8 in.,wt.38.8 lb

35_________720 90 910 12 36
Notes:* Red Top, Starting, Auto Posts, L-9.3 in., W-6.8 in., H 7.6 in.,wt. 32 lb

7535_______720 90 925 12 36
Notes:* Red Top, Starting, Dual Top-Side Posts, L-9.4 in., W-6.8 in., H-7.6 in.,wt.33.1 lb

recordmanv

I have a redtop 720 cold crank in my SC. No problems. Save the weight. Don't forget the bolt down bracket. I recall the bracket being expensive, like 60 bucks.... Good luck.

brg2290

Thanks for your reply recordmanv, it is good to know you are pleased with the lighter battery. I did order this Optima Battery Adaptor Kit from AJ-USA for ~ 31 dollars...should do the trick.

DeckardFC

I have a Redtop in my 1990 RX-7 and I totally recommend one. 7s take a bit to crank and I have nevr had 1 problem. I am getting a 83 911SC next week and that is one of the first things I am goind to get. Look into the yellow top too, only 10 dollars more.