65 Barracuda with factory 318??

Warranty replacement is a possibility,but it would still be a later-than-'65 block as the LA318 just was not available in '65. Special ordering for paint,options,etc. is again possible,but not for the LA 318, which was simply not available in 1965,and like a previous poster replied,the A block(so-called "wide block") 318 was too wide to fit the small, early a-body engine bay.

So,without seeing the car,my assumption would be that it is a swap-in, or it's a 273,possibly with incorrect letter stampings on the block ID pad .

As an aside, my '67 Dart has "C318" stamped on the block ID pad,but the block casting number ends in "273",and, when I recently re-ringed the engine, I installed 3-5/8" ,273-bore rings ,which is what it is....a '67 273.