9Z535816 is the partial VIN from the vehicle. 9 is the model year (1969), Z is the assembly plant (St. Louis) and 535816 is the sequence number of assembly. LINC-MERC sequence starts at 500001 so it should be a 460. I believe they were rated @360HP that model year.
The block casting I.D. No. C9VE is a 429/460 block. For further I.D., you would need to look for the engine tag, carb I.D.tag, etc.