I took my battery to advance auto to test and they said it needed replaced so I just bought a 51R battery while I was there but it only has 410cca with a 70 reserve. It was their silver brand. I cant find a solid answer on what the FD needs. I have a pretty stock car so it wont be too demanding. Should I just use this one or take it back and get something better.

 

I believe the standard CCA's for the car is 550. I've seen people use 500 CCA's, but I would shot for a battery around 550.

 

You're going to lose some reserve capacity with the smaller battery. Only makes sense, doesn't it? But then you're also saving weight, about 10 pounds, where you want it least.....out beyond the front axle.

You've already found that this new battery will start your car. Unless you let your car sit for a month at a time in cold weather, you're probably not going to miss the reserve capacity.
Make sure the car is started and idled / run for 15 - 30 mins once a week, and I'll think you'll be OK.

 

Well actually I havent put it in my car yet but i had no doubt whether it would start the car or not. My car definitely sits a lot though... thats what Im worried about. I dont drive it once a week. Currently I only drive it like 1-3 times a month. Hopefully that will change soon though.

 

If you're an infrequent driver, and you live in a cold climate, then yeah, you may be a candidate for a stock size battery. On the other hand, you could stick with the lighter battery and buy a trickle charger (which may come in handy for the stock size battery anyway.....they can wear down too if not driven enough.) I don't have a trickle charger, but it you get one, you'll want to make sure it has sophisticated enough controls that it won't overcharge the battery.