How to replace oil in a 7.5 horse Ted Williams lower unit

[Harold 1965]

I really need help on how to fill the lower unit on a 7.5 Ted Williams motor I found the lower fill hole screw but I cannot find the top one for this engine and I don't know where the model number would be located

 

[brim_buster]

Model number will be on the transum bracket. Unscrew the plug and drain out oil. Turn motor upside down and refill till full