new old truck with problems

Hello, I know I probably sound like an idiot on here but I just recently bought a 72 chevy pickup for a hobby truck. My problem with it right now (and Im sure there will be many more) is that it shoots fire out of the top of the carburetor. I looked at the firing order and did find that the back 2 spark plug wires on each side were crossed and that helped it run a lot better wthout the fire and everything. Went out and started it up a little while ago and started firing up again. Any suggestions on what it might be? Dont think its the timing because when it's running, it seems to be pretty smooth. But then again as you can probably tell, I am new to engines other than the changing the oil type stuff. Any help or suggestions would be greatly appreciated!!

Hi , would say give it a Good tune up plugs ,wires ,cap, rotor, and check your timing , also make sure your vac advance is working, have fun Slim