1988 Ford F-150 very hard to start

I have to turn key and give gas for more than 30 seconds until truck finally fires. Once it fires I have to give a little gas for a minute and then it runs fine. It has new plugs wire and distributor cap and button all replaced within last month. I do not think it is fuel because the bleeder valve on the fuel rail is getting gas to it. My friend suggested my timing could be off but I am not certain bad timing would create this problem.