fuel pump on 401 is upside down compared to 304

tankcj

My 304 in my CJ has the fuel lines coming out of the top and the 401 I'm going to install has the fuel line coming out of the bottom. I see where people have said you can't mount the fuel pump upside down so is there a different part number for the 304 in a CJ compared to a 401 even though they are the same block externally?

tufcj

AMC used several different fuel pumps depending on the year and application (and what they could get). I run a Carter high flow pump on my AMX. Much better than a factory pump. About $75 at Summit or Jegs. Bob tufcj

1980_Cj7

The fuel pump that was on our 401 when we got it had the fuel lines coming out the bottom. I bumped the fuel pump when we were unloading the engine and bent the valve housing. It's super flimsy. I tried to straighten it up, but the pump wouldn't work, so we had to replace it. The new one had the lines coming out the top. I had to reconfigure the brand new hard fuel lines I had just custom bent! You can't just flip the fuel pump over because the mounting flange isn't symetrical, plus the operating lever is offset in a front to back direction. The pump will only go on one way, but apparently was made in two different orientations.

AMX69PHATTY

The Carter Super Street pump is #M6906, lines come out the bottom.
As mentioned, different pumps used at different times.
Would imagine fuel lines on top is better for off-roading.

oldscout401

As 1980 Cj7 said. There are two versions of AMC fuel pumps. The other 401s I have are the same has the one you got from me. It should run fine just the way it is, or you could run a high prefomance pump. The 401 in my CJ5 was having vaporlock issues in warm temps and high altitude so moved the fuel lines from inside the frame rails to the top of the frame rails and I'm running an electric pump near the tank now. It seems to have solved the vaporlock problem. Good luck.

tankcj

oldscout401 wrote
As 1980 Cj7 said. There are two versions of AMC fuel pumps. The other 401s I have are the same has the one you got from me. It should run fine just the way it is, or you could run a high prefomance pump. The 401 in my CJ5 was having vaporlock issues in warm temps and high altitude so moved the fuel lines from inside the frame rails to the top of the frame rails and I'm running an electric pump near the tank now. It seems to have solved the vaporlock problem. Good luck.

Thanks Lynn,

It looks like the CJ 304 was the strange one with the fuel lines coming out of the top (the 360 I have is also like the 401 with the fuel lines coming out of the bottom). I'm just starting to get ready to pull the 304 and collect parts for the 401 (had the carb rebuilt, new pan gaskets/seals, sandblast and paint all the accessories). I hope to have it complete in a month or two so I'll send you some pictures. :t:

1980_Cj7

I personally like the lines coming out the top better. Makes for more direct routing to the carb. You don't have to make a U-turn with the supply line. Plus it puts that flimsy part of the fuel pump up more out of harm's way. Gets the line from the tank up higher too.