couple questions answered FAST!!!!!!!!

ok i have 2 questions tha i need answeres fast on. first one i did the bag set up on my sonoma in the rear and i'm making it a hopper when i tried hopping the back it doesn't hop i need some restraint on it so the back wheels will carry off the ground with the momentum so what have other ppl done? should i hook up a chain to the axel like the lowrider hydro cars do???

2nd question i will not have heat in my truck and would possibly like to take the heater core out how can i bypass this? or do i need that heater core? its a 95 sonoma

thanx