Passing along this "fix" to guys/gals that are still running an Olds with logs. This helps to prevent distortion/warping on the siamese port on the log. The photo shows the basic set-up. It's a piece of 1" wide by 1.5" tall aluminum barstock that I attached to the top of the log with a clamping arrangement. I filed the top of the log down a little to get reasonably good contact with the aluminum barstock piece. The barstock is through-drilled (0.50" dia.) and tapped on each end for 1/2" NPT barbed nipples. The water through-hole is offset (centerline is 1" away from the side that sits on the log port) to provide additional thread engagement for blind-drilled 1/4-20 tapped holes on the bottom side of the barstock piece. 1/4-20 bolts (or threaded rod) go on either side of the siamesed exhaust port, into the blind-tapped holes, to clamp the barstock piece on. There's a thinner piece of aluminum (or stainless) barstock that spans the siamese port on the backside to complete the clamping hardware. It has two 1/4" (clearance) holes in it for the 1/4" bolts/threaded rod.
The whole contraption goes on/comes off pretty easily. Been running this on a set of logs for almost 20 years with negligable distortion/suck-in. You could use some heat transfer compound to increase the conductivity between the barstock and the port, but I haven't. I run the water through these first, then into the engine.
Other: Don't use the siamese port exhaust bolt to attach the manifold. It'll just dump unwanted heat into the aluminum. Use RTV instead of exhaust gaskets.
Hope this is helpful to someone out there.
Matt
