The engine, for the redesigned McDonnell F3H Demon motorbike, had a name change to J35 after it was modified to a thrust of 7400 lbf.
The Allison J71 was a single spool turbojet engine, designed and built in the United States. 
 It began development in 1948 as a much modified J35, originally designated J35-A-23. 
 With the afterburner, which most models carried, it produced a thrust of 7400 lbf . 
 The successor to the F2H Banshee, the Demon was redesigned with the J71 engine after severe problems with the Westinghouse J40 engine that was part of the original design but ultimately abandoned. 
