I've got a copy of that book.
It is awesome and is about 2" thick!!
If you ever see it in a book shop BUY IT as it is no longer in print.
That 18R-G looks so nice.
One of the funny bit of trivia about that engine from the book:
Toyota let the homologation expire on the twin cam engine in the RA23 so they had to use the 8v single cam engine till the RA40 was brought out with the Twin cam engine.
Just shows how lax manufactures were about keeping competitive in the WRC back then.