It's not marked because #1 can be just about anywhere. When the engine comes from the factory, it's always the same, but if the distributor has been removed, #1 will be whereever the rotor is pointing when #1 piston is at TDC at the top of the compression cycle.
where ever you want it to be just make sure you put the motor at top dead center on cylinder number one and stab the distributer where the rotor points at on the cap is number one and just go clock wise order and use the Chevy firing order
its 1-8-4-3-6-5-7-2 on the distributer number one plug wire usually points to # 1 cylinder front driver side of engineand the distributer turns clockwise Or: http://autorepair.about.com/od/enginefiringorders1/
Your distributer or your coil
get the first piston on the engine TDC (top dead center) take the cap off the distributer and adjust it until the rotar is pointing at #1 cylinder then it will be enough in time to start then use a timiing light from there
no completely different motor
should be in a straight line from center of the distributer cap to the #1 cylinder, or pointing at the #1 cylinder
start engine ,plug off vacuum line to advance on distributer ,set at 6-8 degrees btc with a timing light hooked on #1 cylinder,tighten dist. , hook vac. hose back up.done
About 8.5 to 1
10.5-1
18436572 The #1 cylinder piston must be up on the compression stroke when the rotor button is pointing to #1 plug wire on the distributer cap. The firing order is counter clockwise around the cap.
The 83 Chevy C10 comes with a 305 but not a 350. The 350 is an option on the 3/4 ton but not the 1/2 ton.
1-8-4-3-6-5-7-2