83 Chevy C20 Suburban 454 engine wiring

[blakeduren]

Hey square body fans,
Two questions:
1. My 454 HEI distributor has a factory wire running to the TACH spot on the cap...but this is not a truck with a tach...what is this for? AND I want to add a tach...is there a great place to splice into this?

2. On the drivers side valve cover, there is a electronic thingy bolted down...factory wiring harness...is this part of the cruise control or the turbo 400 down shifting?

Thanks in advance