Small Starter Battery

I have a really long car, and when I first relocated my batteries to the back it seemed like it took just a second longer to start the car.  When I asked someone about this they said it is because the drain of the wire going from the back of the car to the front.  Now in my new car (same car as earlier but a 'new to me' one) I am still relocating the batteries to the back and have a little bit of room in the front for a small battery.

So, i am tryign to find the smallest battery I can put up there to start the car with and still have 2 batteries in the back of the car for back up.  I currently have a Rockford Fosgate Battery, and a Yellow top Optima battery.   I hated running just 2 yellow top optimas due to the hour it would take to recharge one if it ever died.

So, my main question is: what s the smallest battery made that I can put in the front of the car to use to start the engine with.

95 caprice wagon - 383 stroker - corvette starter - powermaster 200 amp alternator.

Size the power wires up to the engine compartment and you don't have to worry about a battery under the hood.. this isn't a new problem for street rodders. Those people will start supercharged big blocks with batteries in the trunk. Your motor should only draw around 300-400 amps to crank. You shouldn't see very much voltage drop with the correct sized power wires.

Jim