1984 Mercedes Benz 500sec Won't start

Hi! I contributed on 5-31 and was going to get back to you regarding a question I had sent and you asked for more information. Since that time, my neighbor has put another engine in his Mercedes and continues to have problems. So, here is the new problem:

Why is gas filing up and dripping our of the air rails? We are getting plenty of spark, but no indication of spark. Even cranking for 60 seconds, there is no backfire.

Is it flooded? Thanks. Jim