Distributor differences?

For the distributors...shouldn't be a difference, but make sure you check out the rotor. Earlier distributors had the "big" rotor while later ones had the small rotor. They should both have the small rotor but I'm not sure when they made that change.

E3's kinda suck and they tend to crack, and they don't flow as well from what I've heard. You're better off with an E6...by the way, if you have an '86 TC engine it should have an E6 already on it.

Ring gap really kinda depends, you have to just put them in the block after you have it honed or bored, square it in the bore with one of the pistons, and check the gap, then compare that to the recommended specs. Sometimes you'll have to file the ends a bit, sometimes you won't have to do anything.