This is one of the great things and one of the bad things about conversions. We all do things differently. I use both the idler unit when I can and do the modifacation to the hydraulic fan pump on many of my conversions and ones Ive helped without the need for custom radiators. I have even used the hydraulic pump in hilux 4x4. I am presently working on a bolt in alloy radiator for surf as well. Already have extractors for surf as well. Your machining job looks good. Cheers