I believe Lambert Co. was pretty much The Go-To upfitter for NAPCO conversions of all sizes in SoCal.

I haven't looked in quite some time, but PeeWee's " Napco Owners Group" website had quite a bit of info if it still exists...Josh's "NapcoPowrPak" had lots of real hands on NAPCO technical info but it is long gone...

Nice truck, Have Fun!