red-line motorsports

hi everyone.
i found this site looking to get help with my 13b. i purchased a snadrail with the motor in it. it sat for about 6 months or longer. it has a weber carb on it. i have replaced the fuel system,plugs and wires as well as changed the oil.
when i try to start it all it does is crank. while cranking it pops and throws flames out the tail pipe. can anybody please help im starting to get dicuraged