Here is the text for page 8.
だめだ！！だめだ！！日本初の『実物大漫画』に挑戦しようと思ってかいてみたが それじゃ 話が ぜんぜんすすまないうちにページがなくなってしまう！！失敗だった！！ 不二夫
Stop!! Stop!! I wanted to try making Japan's first "life-sized manga", but the dialog is eating up all the pages!! It's a failure!! - Fujio.
"dame" is generally used to mean "no good", or "can't be used in that way". In this sentence, Fujio's stopping the story flow because the life-sized panels idea isn't working out like he planned. I debated using "cut! cut!" and treating the manga like the filming of a movie, but "stop! stop!" works just as well.
中落合のツツ井 サオンドの前に たってる易者にみてもらったのだ！！
The fortune teller in front of Tsutsui Sound in Nakaochiai told me!!
Nakaochiai is a district in Shinjuku, in Tokyo Ward. "ツツ井" may be a play on "津つ井", which is the name of a number of different shops. I'm assuming that ""津つ井サオンド" (Tsutsui Sound) was a real record shop, or something similar back between 1967 and 1976 when the manga was running. Nothing of that name shows up in a google search now.
あっ あの人は よくあたるって評判なんだよ！！
Ah, that guy's fabled for always being right!!
せっかく 金をはらって あたらなかったら ソンをするのだ！！
If he's wrong, then I will have wasted all that money!!"
"ソン" is treated as meaning "loss" here, so "son wo suru" would be "with loss to do". That is, "the money I paid would have been for nothing".
Papa, you're an idiot, you're going to die!!
Therefore, if he's right, there's no loss!!
"atari" is used throughout this page to mean "hit the nail on the head", "to hit the target", "to be correct". I'm keeping the language simple here.
If you die it's a loss!!
It's better than being wrong and losing the fee.
If you die, you won't be in the house any more.
"If you die, you won't be here anymore" would have been a more natural way to set up the joke, but I wanted to keep the reference to "ie" in the translation.
You're being stupid. When I go outside, I'm not in the house any more.