Heat venting through when windows are down and not up?

ok heres the deal, and nobody knows why its doing this....so somebody on here knows, just a matter of finding them....ok so when i have my windows DOWN, hot air circulates and it has a slight engine smell to it, but its heat like the heater is on. when my windows are UP, no air circulates through the cab, and stays nice and cool. anyone know why its doin this? it was after a bodydrop and the ac blower motor hole is filled in with sheetmetal and every other hole that was on the firewall....help meh!

heres a stab, i had a 97 mustang Gt, that had 6 cats! anyways, when i crack my windows or roll them down, i can feel the heat coming thru the floor, and visa versa, windows up - no heat. You see, what happens is with the windows up, pressure from inside the cab is keeping the heat from rising thru the floor. Once you crack one window, a vscuum is created in which the pressure in side the cab of the vehilce is released out, bringing the heat from your exhaust under the floor board. i placed a water heater insualtor kit from Home depot under the carpet, reduced the heat signifiacantly!.. I hope this helps ya! L8

like a heat sheild? does it need to be under the entire carpet or just in the front half? that does make good sense though

yeah. and with a body drop, the exhaust and engine are usually closer to the floor. heat is closer too. his idea works. so does dynamat or the equivalent, or undercoat/bedliner. anything that makes it harder for heat to come through. drive it around for a while, then put your hand on the floor and find the hot spots. i would double up those, and full sheet the rest.

alright, thanks, anymore ideas would be helpful, but there are none i can think of