A parts store or on a car at car shows. Old auto repair books.
The #1 cylinder should be the first plug clockwise from the electrical connections on an HEI distributor. Or, the first plug clockwise from 3 O'Clock when facing towards the rear of the vehicle.
go to a shop that's your best bet
I have one but cap and vaccuum advance are missing.
It should be marked on your distributor cap. Just find the wire next to the one and follow it to the cylinder.
We can not provide you with a picture.
www.msdignition.com/pdf/8356_frm25675.pdf
Easiest way to find it is to set #1 piston at TDC and remove the distributor cap to see where the rotor is pointing. It should be pointing to #1 cylinder position in relation to the distributor cap.
From a Chevy Dealer.
inside of the distributor
Chevy 350 cylinder 1 on top dead center timing mark aligned , rotor should be at 7:00 (standing at front) distributor cap should be square with engine 7:00 should be at #1 on cap
It does not have a distributor, it has coil packs. Look at the link below.
It should be marked on your distributor cap. Just find the wire next to the one and follow it to the cylinder.