Failing that and if you must have the motor that way up, take the middle spacer out, clamp the two frame sides together and drill new fixing holes where ever you want the spacer to be, suggest directly in front by about 15mm. You don't need to counter sink the outside of the holes, use the screws to hold it all together, even though the middle ones will be proud, solder on the inside of the frames with plenty of flux so it works around the spacer and thread, cut off proud head and file smooth. The two outer ones will form the strongest joints but the middle one soldered well will not give you any problems or come adrift.
Retain cut off counter sunk heads, stick them in the old holes and flood solder, then file and clean up to leave a smooth surface on the outside.
MD