170 was the base engine in the very early 65s (often called 64 1/2) when the first optional engine was the 260 2v.
It could be a replacement as could a 260 V8 as a replacement for a 289.
My '64 1/2 vert. Ordered May '64. D code 4 speed, handling package, caspian blue, accent group, Ford blue manual top.
'68 vert. driver. Owned since Apr '78. C code AT, AC, PS, P disc B, PT lime gold, standard black interior and top. NOS RF fender and left quarter.New top and folding glass.