What other work has been done to this engine?
For A Dizzy install..
Number 1 cylinder TDC, compression, Timing marks aligned, Both intake valves closed , no pressure on the lifters (not too much slack either..) If you can't co~ordinate these, you have mechanical issues (timing chain/gear issues..)
Drop the dizzy in, and watch the rotor, It will advance clockwise a bit, this is because the gear teeth are diagonal cut, It will go about a tower in a half in some cases..Note #1 and the amount of change with a pen on the bottom of the Dizzy, and then withdraw It.
Line the oil pump shaft up to that location with a large screw driver, and reset the dizzy, for number one plug tower, allowing for advancing Difference as the gears seat..
The easy way to do this is make magic marker lines on the base of the dizzy, for exact #1 plug tower, and the difference of rotor movement as it seats..due to the cut of the gears..(I.E...#1 and the amount of distance BACK required to make it sit on #1 plug tower when bottomed out..)
#1 plug tower in the stock location for SBC's is 5 to 7 O'clock, (depends on year, and obstructions) 7 is usually good.
Direction of rotation is clockwise.
The F.O. is 1 8 4 3 6 5 7 2..
Put on your hold down just tight enough to hold it but enough to forcibly move it by hand, and start it up..set your static and total timing..Start and warm, at idle, about 650 RPMs manual, 950 RPMs Automatic , full open choke.
Hook up a timing light..
Static 10 to 12 is a good starting point advance defeated and vacuum line plugged.
Total around 34 to 36 is usual on a stocker with advance hooked back up..
Tighten down the hold down, set your idle for 650 Manual trans, 950 Automatic, and drive it .. hammer it on the freeway, If it pings or runs hotter than usual, retard it a few degrees..If it dogs, advance it..Try also lugging it up a steep hill highest gear as slow as it will pull, If it pings check the timing again.