Originally Posted by chucksrt
The vortec dist has very little side to side movement. Moving it a tooth in either direction just causes it to be way too far out to get into time.
If the theory you're going by mattered, then just use #6 to time it. Put a TDC mark 180 degrees from the line now on the damper.
But the whole thing revolves around setting the distributor in and having the oil pump drive shaft indexed correctly
. In some non stock installations, there may be a lack of clearance that will make setting the timing a chore- but there's almost always enough adjustability to allow setting it right w/o clearancing the firewall or grinding, etc.
The rotor turns about 2" CW as the distributor engages the cam gear and is seated (on a large cap HEI, less on a small cap HEI), so set the rotor that far CCW to allow the gears to turn the rotor into position. The oil pump shaft can be easily turned w/a long screwdriver to allow the shaft of the distributor and the pump shaft to engage correctly.
Be sure the distributor isn't bottoming out by temporarily removing the gasket between the distributor and intake and setting the distributor into position. Then lift up on the top plate to be sure there's still a small amount of clearance. If there isn't clearance, use nylon spacers made for setting the distributor height. The shim kits are sold through Summit and Jegs, etc. from Moroso, Mr. Gasket, Jegs brand, and others as well. The kits typically contain 0.030", 0.060", and 0.090" (or 0.100", depending on brand) shims. Don't just stack fiber washers, they'll become oil logged and crush down and you'll lose the clearance if the clamp is tightened.