i came out of the driveway last night i goosed it so the tires would turn over then let out. coasted a few feet and their was a loud pop then the truck died wont start back. took it back home to the garage and tried to turn the motor over by hand but it will only go so far then catch. any suggestions on what this could be. i am going to start taking her apart tomorrow. do you think it could be a dropped valve or a broken piston rod or what? please help in any way. or is it telling me that it is time for a 408?

 

Could be several different things, How many miles do you have?

 

i'd be looking for a dropped valve or broken timing chain.

 

timing chain, is a real possibity

 

it has about 8k on the motor

 

Hard to say could be alot of things, you might not see a broken valve with just the valvecovers off, unless a keeper or retainer failed. The head of the valve could have broke off though and leave the stem in the spring. If the timing chain broke then there could be bent valves.
If its locked up it could be a rod. or a piece of the valves stuck in there some where.

 

when you it catches it has a little metal clang noise to it.

 

****** the front cover off and take a look. it dont take just little bit of time.

 

when it popped it then house something like a glass shattering should then smoke came out from underneath the truck but not from the exhaust

 

Are you sure its in the motor? Maybe the trans or TQ?