Why doesn't Goku use the Super Kamehameha in DBZ OR DBGT?
Goku only says "Super" Kamehameha Wave because he was trying to describe his new found power. From that moment on, the Super Kamehameha Wave becomes a "Kamehameha Wave" only matched by his sheer power to back it up. As his power level surpasses that of Dragon Ball he no longer is forced to use such a name for the attack because the power of his wave grows with the power within him. Super Saiyan, Ascended Saiyan, and Super Saiyan 3 each notably have a stronger Kamehameha Wave by their "upgrade", respectively.
Krillin tells Goku that if Kami dies, they could still bring him back using the Dragonballs. However, Goku of all people should know that if Kami dies, the Dragonballs will also disappear.
Goku: Your ego is so bloated I'm surprised it even fits in the ring. I'm going to enjoy taking you down a notch or two.
Piccolo: Why don't you do us all a favor and leave the one-liners to me?
Goku uses the Super Kamehameha once again in DBZ : The Plan to Destroy the Saiyans.
Original Air Date: February 8th, 1989
Japanese Title: Unleashed! The Final Super Kamehameha
Blue Water Dub Title: The Ultimate Kamehameha Wave!