I tried to install a new heather core in my 1968 Convertible Firebird (with out air). I followed the Chiltons and 68 service manual to a tee, but after I could not line up the intake and outtake tubes the the fire wall holes I tried to bend one of the copper tubes and broke it off. Frustrated I ordered a new one. Upon doing a dry run to line up the copper tubes with the fire wall I noticed the way the tubes are bent and the narrow placement of the tubes they will never go through the fire wall holes. The only thing I can think of doing which would work but would be labor intensive would be take off the fender and blower housing. What is your experience on the install of a Heater Core. Need your input. Newbie to wrenching, first mid life crisis project. Thks guys.