While cranking engine voltage drops to 9 volts is this normal.. when I bought the truck the battery was dead. They put in one that has no labels on it and looks to small for tray

 

no its not normal...you need a new battery...the correct size also..

 

+1, Not good. I recommend a new big honkin' Motorcraft.

 

Prolly why I'm having issues.... whats the correct siZe or group and crank amps. I know the altenator is working hard can hear it

 

buy a batt. from the dealer...you will be surprised at the price...and you will get the correct 1...you install it...

 

A 65 group size. Min O.E. CCA rating is 650, but you can get way higher. Mine is rated at 880 CCA. A good battery will be a little over 11v at crank.

 

Around a 100. At dealer? At auto part or Wally mart there 110 or so


11volt at crank. Dayem ok. Mine is at 9.

 

The old way to check for starting related battery failure was that the battery voltage should not drop BELOW 9.6 volts on a fully charged battery during engine crank. Now they have those battery testers so it may eliminate that.
Get the highest CCA you can find. You may not need it but it should not cost as much. If you wanted to spend some money, here is one I am thinking of. I will be keeping this truck for at least another 5 years;

http://www.batteriesplus.com/product...-Optional.aspx

Higher priced but it has the cca and is rated for big sound systems too, something people forget about. They make them for different years and engine sizes too, it's on their website.

Good luck!