we have an 89 Chevy 1500 350 getting spark to the distributor cap but not to the wires what could possibly cause that we have replaced the distributor cap distributor coil and the timing chain

there is a little carbon spring loaded button at the center of the cap that must have fallen off....just get a NEW cap, because even if you find it will be trouble for you~

could dig deeper, like resistance from the positive coil to ground and how many thousand volts are being produced....and y'know a shower in WD-40 will temporarily STOP the high voltage leaks to the atmosphere (you can't see 'em, but they are there)~ as ALWAYS I would like you to take the main 1/0 battery cable that connects to the chassis ground and wirebrush all traces from high-voltage exchange on both lug and body~

With distr cap off have someone try to start it. Watch the rotor button . Make sure that your rotor button is turning around and around.

If rotor button does not turn then inspect that it is positioned on the dist shaft correctly. If still will not turn you will need to pull the dist out to inspect the gears on the bottom of it.