ok, my truck has been sitting out for almost a year, I put supreme and stabilizer in it before I stored it. I just went out and got it today, checked fluids and they are fine, hooked up jumper cables to it for a while and figured the battery is now 7 years old anyways so Ill go get a new one, so I replace my les schwab 450cca with a 625cca interstate battery. popped off the air cleaner poired a small amount of fuel down the carb and it fired up pretty quickly. now the sticker on the battery says 05/07 so it cant be an old battery that was still stocked. I drove it to a friends house, then to the ferry, then top the gas station to air up my tires, total of maybe 25 minutes drive time, and maybe 7 or 8 starts and then when I go to start it it wont crank over. so I call my girl for a jump she gets there I start it and the voltmeter says 14 volts while its running, so it cant be the alternator right? and its a new battery, I cleaned the battery clamps and obviously the posts were nice and clean, they are nice and tight? what should I check.

you should have checked the battery voltage when it wouldn't start. sometimes starters/solenoids won't work at twelve volts, but will work if jumped by another car at 14 volts. you still may also have a bad alternator. it is possible for it to put out 14 volts but too little amperage.

Was it cranking slowly, just clicking or doing nothing at all?

it cranks slow, or just does a half a crank or so and stops. weird thing is after I got it back from jumping it I turned it off and didnt touch it til I just got back from work, jumped in andc it cranked away. Ill have my alt tested soon.

Here are my thoughts:

Check your battery connections again. The new posts may not have been as clean as you perceived them to be.

Check (or just go ahead and clean/tighten) your battery ground at the inner fender and engine.

Check the positive connection at the starter.

Check ignition timing. It may be too far advanced, which may cause slow cranking when hot.

The starter may be going south on you.