I would opt for the 46AX conversion their all good davis heads available for all

wt irvine 53 550 gm
OS 46AX 463 gm
MVVS 40 472 Gm the 49 may be a bit more ( do not have the 49)
MY 46AX gobs of power it is slated to go into my pulse 40 when plane is finished
all weights are with mufflers have all 3 engines martin
typo on original post have the MVVS 40 not 49
Davis thinks I can get a hover with a 13X4 with the AX46