For the last 2 months I could not get my webers tuned and losing power during take off. I went to the mechinc and check out carbs. Tuned best he could and we where even talking about swapping them out for new. So he pulled on passenger side carb and it was fine than pulled on driver carb and it was loose? Look with mirror he noticed large crack. We than called Henry from Intermiccanica he sent new manifold in less than week. We intstalled it today. Car purred it was perfect. So they started to tune cards again with floats. Well passanger side was crack as well. Much smaller crack so car runs great but Henry is sending new manifold again and we think that because they were ported it left wall very thin. So there dealing with that by providing continuous weld at base. I hope this cures this issue.
Original Post
