Not sure if this applies to your application but on SBC..I remove the plugs so I don't fight compression. There are two TDC's one is the compression stroke (Piston at top of cylinder) and the exhaust stroke at the bottom of cylinder, for lack of a better term. Using your timeing mark put your finger over the #1 spark plug hole, and as it comes up to the top of the cylinder air will push thru the hole and push your finger from the hole. Line up your timing mark so it is on zero and the balancer mark. You should be at TDC. If for some reason the balancer or the timing marker have been changed (Seen it happen) a piece of wire can be bent in an "L" shape and put into the spark plug hole to "feel" if the piston is at the top of the cylinder. Do this gently so you do not scratch the top of the piston.
Then figure out which wire on the dist cap is to be #1 and mark the base of the dist with a sharpie (Small line on the base)and also the cap with masking tape. Line up the rotor with the mark on the base of the distrubutor and stab the distrubtor . When the dist is seated, check again, bring your engine to TDC on the compression stroke and look at the position of the rotor. Should line up with the mark you placed on the distributor base. Also check to make sure you have clearance so you can rotate the dist. for timing purposes. If the rotor does not line up with the mark you have missed it by a tooth or two on the dizzy gear, try stabbing it again. Remember the dist will rotate slightly because of the gears.
You will then need to find out what the firing order is and the rotation of the dizzy, to route the rest of your plug wires.
Here is a link for the firing order and rotation for a SBC
http://www.boxwrench.net/specs/chevy_sb.htm
