The heatercore is from an opel rekord 79-model. The intake/outlet was not like your drawing, but came out on the side of it, so i hade to cut off , make new holes, and solder in the front.
I paid about 15 bucks for it from a scrapyard.(and Norway is an expensive country, i'll promise u!!
The mounting for the waterblock is made of plexi.It's mounted in the 4 holes in the motherboard, and with a screw in the center of the plexiboard to add pressure to the waterblock. The waterblock is homemade. I used drill to make one BIG cave in the copperblock..hehe.. no spiral inside. just one big hole