How do i set the timing in my 95 sonoma with an older carberated 350 from start without taking timing cover off?

There are two kinds of timing, cam timing, and ignition timing. You don't adjust cam timing, it is set when the timing chain is installed. The timing chain cover is supposed to have a pointer welded to it with marks that line up with a mark on the harmonic balancer. (depending on the year of you engine these marks veri in appearance. Ignition timing is set while the engine is running with a strobe light that is triggered by the number one spark plug. On this engine (if it's stock) around 8-10 degrees BTDC. The ignition timing advances with cetrifical weights inside the distributor as well as a vacuum diaphragm. If either of these fail you will have a performance issue with a lack of power, and acceleration. If you are concerned about the cam gear being worn out yes they do wear out. Chevy made the gear teeth on the cam gear out of nylon to make then quieter, the replacement gears are usually cast iron. If you are thinking about changing the timing gears, the crank gear has to be pulled off with a puller, a lot of guys don't bother since it doesn't wear like the cam gear.