I installed a 5.3 LS in my 1969 el Camino. The only issue that I am having is when I start the engine. I have good fuel pressure, no vacum leaks, it does start it just does not fire off right away. Also the starter does not want to disengage until the engine is running. I need some help on what might be the problem. Once it is running it runs fine. Any help will be greatly appreciated. I just need to know where to start. I have not done a trouble code check yet.