I have a 1966 Dodge Dart GT with the 225 slat 6. I want to go from a 1bbl Holley carburetor to a 4bbl Holley carburetor other than the intake manifold and carburetor what else do I need to do so that the engine runs good? Example: Do I need to advance timing, adjust fuel pedal, or will this be a swap and go. Thank you for any responses. Just to avoid confusion the intake manifold I want to go with is a offenhouser 4bbl. Summit website suggests a 390 Holley.

 

Welcome.

That much carb increase should have a camshaft upgrade.

 

camshaft recommendations. That begs the question will I need to change valves, head.

 

More compression, head work with new valves, springs etc. port work , performance cam and dont forget a set of headers and new exhaust. That new carb just got expensive but if you don't the rest you don't need the carb.

 

After much consideration I think I'm going to get a 2bbl intake and carburetor. I know that will be a lot less work.

 

Have a look at this: https://www.allpar.com/mopar/hyper-pak.html

 

That's a lot of information. Thanks.

 

Chrysler offered a two barrel carb in the seventies I think it was called the super six. But stock parts are our there for this upgrade.

 

Yes that was the super 6 also it was a 226. But the intake manifold and carburetor will work for the 225 all I should have to do is advance the timing.

 

Why not get the 4 barrel and 2 barrel adapter so your ready when you want to rebuild and really hot rod it?

 

That will be down the road at that point I may even drop a 318 in it. I was just trying to remember what all I needed to do to go to a 4bbl. I haven't worked on Mopars in forever.