will not stay started

i have a 84 ford f-150 that has a modified 351w and when i am able to get it to start it will only stay started for about a minute even when im pushing on the gas pedal and i will even have a brand new battery on it and i also got a new alternator and starter on it and i still wont stay started i am also running a cd play wit 1 12" sub , 2 10" subs 2 6" speakers and 2 4" speakers my engine also has been bored out i am also get a squeal from the belts at 3000rpm wut shout i do to solve my engines proble with not being able to stay started and how do i fix the sqealing

please help me with this as for i need if for the winter thankx to all those that will help

and who ever it is that think they have an answer for this email me at horntaleviper@hotmail.com thanx