What goes to the holes in question? If I understand your question,you now have 3 holes,but the new covers only have 2.That means something won't have a place to connect. you might have to eliminate one hose,or maybe Tie it into another one with a T fitting.
Speed


1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck