I’m probably the club member that Soybean was referring to so I’ll jump in here and clarify something. When I did my intake manifold I drilled out the four intake to exhaust manifold bolt holes to 5/16-inch and inserted a piece of 5/16-inch aluminum rod into each hole. I bolted the intake to a spare head and made up a 1/2 inch steel plate to bolt to the carb mounting surface to act as heat sinks during welding. After everything was bolted up I welded the top of the rods in place and ran a few beads along the sides where the runners meet the riser portion. I went slowly with the welding as not to warp anything. After all the welding was done I milled off the bottom of the intake and milled a wedge out of a piece of billet aluminum just like ftl did in post #26 of this thread.
His pic here:
http://www.opelgt.com/forums/attachm...tachmentid=689
After I milled the bottom off I ported the intake per RallyBob’s directions, having the bottom open made the porting easier. After all the porting was done I re-bolted the intake to the head and carb plate I made and welded in the wedge/bottom plate and the bottom of the rods I had inserted in the holes, again going slow to minimize warping. After everything was done I checked and nothing was warped but I did mill 3/16-inch off the carb mounting surface just to be sure and also provide clearance for the ½-inch heat insulator I put under the carb. I did not mill the head mounting surface of the intake because I could not figure out a way to resurface the intake and exhaust manifolds together inorder to maintain the width of the mounting surfaces.
I did have to reshape the OEM steel heat shield a little due to the welds along the sides of the riser portion of the intake manifold. I had free run of a machine shop when I did this so time and labour cost were not a factor.
Brian