78 el co timing need help asap

[78hellco]

I have a 78 el co shut off on me while driving replaced dis cap coil rotor and plugs gets spark but when i crank it over it back fires and shoots flame out carbon is my timing of i bumped the dis out of place when working on it how do i fix and Watson the order on the dis cap for spark wires need help asap got to get to work thanks a thousand

 

[Tank]

First we will need to know what size motor your running, 3.8L v6 or 305 v8 or something totally different?
Site below should help
http://www.boxwrench.net/specs/chevy_sb.htm