Which 302 firing order do you have? Is your engine original? Early 302's 1-5-4-2-6-3-7-8, later firing order was changed to 1-3-7-2-6-5-4-8. Determined by cam. Did you swap wires 1 at a time or all together with new cap?
Best source for modeling of all types. Local chapters across the country, usually meet once a month. Been a member since the 70's. Most have a Facebook page too.
https://ipmsusa.org/
https://calendar.ipmsusa3.org/chapter/ipmsthree-rivers-chapter