I have long tube Hookers matched to the Clifford, have Dual Dutras on a slant in the 83 D150 matched to a cast aluminum Mopar Performance 2 BBL intake. The Dual Dutras were purchased and installed about 2010, so maybe some things have changed, but I had to grind down the manufacturing lugs on the block and add clearance to the manifolds for socket clearance. Nothing major, just trial fit the manifolds to the head with no block and to the head on the block with no intake so you can get a good look.