350 vortec timing issues?

i have a 97 c/k 1500 2wd with a 350 vortec and a auto trans.
i have idling problems the motor races up when i put it in park.
and in drive in all gears. when i shift it jumps into gear.

what is getting to me is it does not do this every time.
it races up more than it runs right.
it is hard to stop and slow down.
it is burning up my torque converter for sure

this is a crate 350 that has less than 20,000 miles on it.
i swapped out my 305 for a 350.
im using the 305 dist,intake,injectors,throttle body,ect...
i have new master comp,throttle sensor, all sensors, modules, mass air have been replaced
do i need a engine scanner to time this motor?
where can i get one?
this is the only thing i can think could be it.
thanks to all who respond111;)
human networking is one of the best ways to further the human race
chip

A scan tool is required and leave the timing light in the toolbox,has to be set with a scan tool.Any aftermarket scan tool will do this job,you go into the data stream and look for cam sensor retard.The spec is 0 degrees.The part inside the distribitor is for firing up the injectors.

I thought a computer change is required when changing from a 305 to the 350. Is this right or wronge?