1966 slant six 170 timing mark

No. It will work fine as long as the engine spins over. Ground lead to ground and other lead to distributor side of coil. Set to the correct scale and spin the engine. Dwell should be 40-45 degrees.
I dont think my dwell is right. Just tried it and it's around 21/22. When I stop cranking ot goes all the way to the left at 60. Do I need set the point gap closer?