Chevrolet: Fuel pump leaking again, 454, excessive pressure, gas cap

Question
I have a 1985 Motor-home, standard Chevy Chassis. E30 The motor, 454, keeps leaking gas out of the fuel pump. There is a pressure relief hole on the pump it blows out of. The shop put in a second one no charge and also put a venting gas cap on  thinking the tank was building up excessive pressure. It is doing it again and I checked the tank, no pressure. Any Ideas?

Answer
SCOTT -
Thats not good -and with a mobile home it can catch fire , what you can do to get rid of the trouble is to get a elect.fuel pump and regulator ,this way you can put a secret switch under the dash to kill the fuel so  the home can not be stolen. and it will be better all around. what do you think..