I have a 70 442 /455 When driving the pressure in tank builds up so that the tank itself expands and when I take off the cap the pressure release seems excessive! I crawl under and see there are 2 hoses that have bolts in them sealing them off?? I assume these are the vent hoses?? I have switched to a vented cap but expansion still exists to I need to put a Vent value like one sold by OPG on these blocked hoses to solve the issue or is there a better way?? Sorry to be so Ni eve on this subject PLEASE HELP THANKS