The E1/Zero-B will go straight in and as already mentioned and you will be needing an MQ valve.
The biggest issue is that EGO frames are to long and need to be chopped at one or both ends.
Pics are of a standard 05 EGO frame and a full lenth cocker body.
And my gat wit cut down ego frame, fully working but still con finished.
Notice how cutting the frame at the rear brakes into the try section and needs something to fill it.
I Guess if you had a front block with asa on it it would be possible to use the frame at full lenth and just plug the old asa holes.