I just put new rings and bearings in my 88 ford F-150 with a 302 in it. Now when I put it in the truck, it wont crank. If I hold the starter button on, and get a breaker bar on the front pulley, it will turn over just barely. This, with the spark plugs out. It is not the starter because I put a good one in and had the same problem. Any suggestions will certainly be appreciated.

mis-matched rod-cap or wrong size bearings ... most engine rebuild kits come with .010" larger main bearings and if you don't have the crank shaft turned they are too thick ... which could cause your problem

awwwwwww man you know better then to trust auto parts stores. you should ALWAYS use plasti-gauge to check your clearances before final assembably

is it automatic? because if you didn't get the torque converter into the right slots all the way back in the pump, it could bind. Also, main bearing caps in the wrong spot. Did you number them correctly? Wrong timming, piston hitting valve. Wrong rods in wrong spot, you name it!