Cold case 756a fitment

Maybe your "firewall" was not stamped correctly at the factory.
Typical off shore product, it all looks good in the marketing ads until you try to install it. I would return it and buy a Griffin radiator.
As soon as you modify it your warranty is kaput.
Not true. We have a 60 day return policy that includes fitment. Basically, as long as you don't stick a screwdriver through the core, it's returnable for an exchange or refund. We also have a lifetime warranty...not prorated. New replacement if it ever fails.