[64 Olds Dynamic 88]

I have an engine code book that identifies the "N" prefix on OLdsmobile engines for 1965 and 1966 Dynamic 88, Delta 88 and Ninety Eight models. It lists the engine as an eight cylinder, 425 CID with 4 barrel carburetor. The horsepower for the 1965 version is listed as 360 with a 10.25:1 compression ratio. The 1966 vesrion is listed at 365 horsepower.
Hope this helps.