Make sure you have your rockers adjusted right. I went to a fella's house who had the same problem you did. I ended up pulling #1 plug to insure he had the distributor set right. I told him to crank the motor over while I held my finger over the plug hole. The motor turned over a few times and now compression. Come to find out he had the rockers too tight. Once he got that straight the engine started right up.
You must have an igntion timing/firing order issue or rocker issue if your getting gas to the motor and you say you have spark.