SB engine rebuilding got ya! School is Open!
Remember to put the oiling hole side of the rocker shafts facing down. Doh!
And NEVER trust a /6 nylon distributor gear with a hairline crack in it for a "test trip" down the road to try your now non-lean burn setup. -At least I got a tow home with my buddies Dodge truck, so the humiliation was far less.