My 74 Nova heater core is leaking.
The car has no a/c.
I was told by some that I had to remove the inner and outer fender to get to the core.
Others say that they were able to change the core from inside, and that I would only have to remove from the engine bay if I was replacing the Blower.
Has any member been able to change a core from inside, if so, any tips would be useful.
Thanks

You cannot replace the heater core from inside the car without removing the blower box assy on the engine side of the firewall. You have to remove the whole blower box assy that is on the engine side of the firewall. At the very least you will have to unbolt the inner fender panel at the back so you can get your hand in to loosen the nuts that hold the blower box on. Once the box is off you may be able to pull the heater core from the engine side but most likely you will need to pull the inside part of the box back into the car to remove the core. At that point you will be replacing the core from inside the car.