There are adapter plates at automotive supply stores where you can mount a 2-barrel carb on a 4-barrel manifold. The one I saw looked like it could be used upside-down (with a spacer to allow room for the butterflies). You'd want to max-out the opening to allow additional flow. If you take the manifold off to do that, match the passage edges to a brand new gasket and scribe a line inside the intake ports. Then chamfer the manifold and head intake passages to allow for max flow.
I'm not aware of any stock or aftermarket 4-barrel manifolds for the 120/140 GM. The 190 is a 4-barrel 170 which is mostly Ford-based.
There are adapter plates at automotive supply stores where you can mount a 2-barrel carb on a 4-barrel manifold. The one I saw looked like it could be used upside-down (with a spacer to allow room for the butterflies). You'd want to max-out the opening to allow additional flow. If you take the manifold off to do that, match the passage edges to a brand new gasket and scribe a line inside the intake ports. Then chamfer the manifold and head intake passages to allow for max flow.
I'm not aware of any stock or aftermarket 4-barrel manifolds for the 120/140 GM. The 190 is a 4-barrel 170 which is mostly Ford-based.
Yes the 470 mercruiser was marketed as a 170 hp equipped with the 2 barrel and 190 hp with a 4 barrel.
Putting a 4 barrel on that old engine would be a waste of cash. Keeping it in tune, make sure there is no excess junk in the boat, check to see if the flotation is water logged and be happy. The closest alternative is to look for a faster boat.
Yes the 470 mercruiser was marketed as a 170 hp equipped with the 2 barrel and 190 hp with a 4 barrel.
Putting a 4 barrel on that old engine would be a waste of cash. Keeping it in tune, make sure there is no excess junk in the boat, check to see if the flotation is water logged and be happy. The closest alternative is to look for a faster boat.
