So I need to change the heater hoses on my 69 XR7 351 (M Code) with no A/C. The hoses are getting old and cracked and it is definitely time. The problem I'm having is that the hoses disappear into the firewall with no visible hose clamps under the hood. Do I really have to go under the dash to change these hoses? Is this the factory set-up or was this the bright idea of a former owner? Has anyone done this job? Is it easy or am I going to be letting loose with a few choice words halfway through it?