are the 87 tuned port 350 motors interference motors? trying to set my timing but im scared ill hurt the engine

Um. Are you playing with the timing chain or just setting the timing by moving the distributor?

the timing is advanced and i dont want it like that so probably the distributor hopefully. i really dont wanna get into the chain

Adjusting ignition timing will not effect valve to piston clearance.

Set the timing to the proper spec, unless you have some mods and/or want to go a bit faster.
The dizzy timing won't mess with the valve/ piston clearance