Here's a link to a heat plate I made.
http://s31.photobucket.com/albums/c355/chevy2inreno/Inliners/ I had a friend with a milling machine that let me hack way at a chunk of billet in his shop. I milled a big hole in the middle of the piece and then welded a plug on top. The water goes in, bounces aroud a little, then goes out the other side. I prefer water heat due to it's consistency and low corrosiveness, compared to exhaust heat. I noticed a big chance in drivability and an increase in mileage.
Dave
