Although Tom L. recommends water heat I'm totally with DrewP on using exhaust heat. After nearly 9K on my 235 setup I can verify that it is easier to plumb, provides the necessary heat, and eliminates the potential for leaks which can leave you stranded on the road. The firing order of the 235 insures a pressure differential and unlike coolant heat, the exhaust heat is instantaneous.
Installation of the Fentons to the Offy intake require a bit of grinding on the intake so they fit properly. The heat plate needed to be trimmed a little so the vertical linkage would not scrub. Also, the head of the manifold bolt where the linkage comes up from the bellcrank needed to be ground down a bit for smooth WOT linkage movement. On your Fenton intake I'd bolt them up and see if you could slide a piece of paper between them to insure a good fit for the intake to the head. You might get lucky!!
You might check out my webshots "Shoebox" album for fitment info for the Fenton exhaust heat.
Dave
