Triumph Repair: battery requires, crank shaft, auto parts store

Question
Just purchased a 78 Spitfire for restoration and it is in need of a lot of help. I wanted to crank it up so I took some minor steps.
1. changed the oil
2. installed new spark plugs
3. filled the radiator
4. oiled the lifters
5. purchased a new battery.
I took the old battery in to the auto parts store and they gave me another, but I don't think the checked the cranking amps on the old battery. It seemed that they were more concerned on the size of the battery. Is there a CC amps requirement for the Spitfire?
I installed the battery they gave me but it seems that the starter is engaging but barely turning the crank shaft. Feels that the battery does not have the juice required to turn the engine. Any help would be appreciated..

Answer
There is no CC requirement.  Any decent battery should be fine. if the engine can spin on its own, then the battery "size" doesn't matter.

It may be more the starter is worn, or the engine isn't as free spinning as it should; You don't say if the engine has been sitting a long time, inside or out, so I'm not sure.

Suggestions:
-See how easily the crank turns by hand/wrench to see if it free spinning or binding.  The amount of force you have to apply will tell you.  You shouldn't have to force the engine to spin.  If you have to apply alot of torque, then you have larger issues you have to investigate.
-I assume you change the oil filter, too.
-Jump with another known good battery to see if that gets you more "spin" after making sure the engine isn't binding

More involved options
-Pull the distributor and use the drill and rod technique (look up online) to prime the oil pump and circulate oil
-check if he bores are rusted, and/or shoot a small amount of oil into each cylinder and rotate the engine by hand to get it worked in
-remove the starter and have it inspected and/or rebuilt if engine isn't binding
-Check the end float (forward/rearward play) of the crankshaft by prysing the front pulley to see how much it moves, if at all.  If its dropped a thrust washer, that could account for its binding.