KVA
Member
Making a 40" bar work will depend on the way the light bar mounts, some have large side brackets and some have brackets that kinda tuck under the bar.
Technically I have 40.25" to work with from one a-pillar to the next or about 37.75" in between each a-pillar. The 40" bar could mount up at 40.5". Of course this assumes I can develop a bracket that connects to each a-pillar on the outer sides. Best bet is to weld custom brackets thus you get whatever specs you need.
Finding a decent led light bar at anything but 10, 20, 30, 40 & 50" in the same configuration is tough.