1965 Cadillac EL Dorado Summer is coming and I want my conv

Hello,

I am wondering what is wrong with this car. It used to run great until my step-dad gave it a "tune-up" and now it runs terribly if at all. I think what may have happened is the distributor cap was replaced but the sparkplugs are now firing in the wrong order. I was wondering if you knew which firing order, or the numbering on the sparkplugs that go into the engine or any other useful tips. Maybe there is something else, but I wanted to see what you guys think before I have to take it in. I've tried already a few configurations, but it hasnt really worked for me.

the distribitor cap now is arranged

1-8-4-3-5-6-7-2

The engine is arranged right now (not sure)

8[]7
6[]5
4[]3
2[]1

(front of car)

tell me what is wrong please!