His distributor is installed in the wrong position and I'd like to use the damper line and timing tab to set TDC.

 

Looks like an engine with Vortec heads, is this an original engine?

Appers to be the long pump which is 7 inches gasket face to front of hub. Short pump is 5-5/8ths.

Different engines put timing pointer in different places.

Factory orientation has the number one distributor terminal pretty closely pointing at the number one spark plug with the vacuum can roughly on a line drawn across tge engine between cylinders 5 and 6.

Bogie.

 

Short w-pump really hugs the timing chain cover. That looks long.

 

Yep, that is a long pump.
Long pump is the only way power steering pump and alternator fit forward of the face of the engine block like that.
Short pump mandates bigger , longer brackets that place alternator above the valvecover with 3/4 of it's mass behind the front face of the block and the power steering pump outboard far enough to be low and beside the side of the block, not out in front of it.

Short pump also has a flat, no dish crank pulley.

Looks like that mess has the alternator adjustment link overextended so far it appears to have bent it or it is starting to come out of threads.
You can also see where the long pump power steering bracket is supposed to bolt to the head, with a short spacer tube between block and bracket....right next to water pump leg.


You know as well as I do you cannot trust the timing tab and balancer line to be a matched set after looking at that bracket disaster bolted up front.

Long pump engine were available with tab at 2 o'clock or at 12 o'clock depending on year and model.....your going to need a piston stop to figure this out at this point.

 

Thanks Guys. Wasn't sure because the points of his tab were only visible by looking under the pump from the front. Crazy. Absolutely no way to hold a timing light on it.
I will have to check where his timing mark is in relation to the key way slot. I can then find a proper tab. 12 or 2. Then, use the piston stop for TDC. Then adjust the dizzy for #1 and position the vac can location as Bogie describes.