Needing some real world experience/opinions- this subject has been beat to death but the application isn't typical. I have a 1989 Chevy full size 4x4, 355cid Edelbrock Vortec TPI,FlowTech Induction roller cam, 700r4, 3:73 diff. Torque has been pretty good with the Hi-Flow.
Having problems with a damaged intake valve on my RHS vortec 2.02/1.6 so I just elected to install a set of AFR 0912 vortec's with a FIRST TPI unit, MAP based ecm is a Dynamic EFI 7747 with WB. Block is a 4 bolt main- studs, as well as head studs, Mahle forgings, stock crank and Scat rods. With iron heads the compression is +-9:1 and this will take a slight hit with 65cc AFR's. The engine has less than 10k on it otherwise I would bump the compression to 10:1 and call it a day.
Cruise on the highway is around1800rpm and with towing 2400rpm, I'll call 5800rpm the shift point.
So I was considering a single turbo to spice things up with the emphasis on highway and towing performance, I've decided to look at oe turbo's Borg Warner or Holset- my tuner suggested a HX35- my reading suggests this is too small. I have the old Edelbrock TES shorty headers and Y-pipe and was going to leave the drivers side as is, reusing the crossover pipe, build a log style manifold with the crossover coming up from behind and below with the turbo mounted on top above the center exhaust ports. The oil drain will go to the fuel pump cover, the cold air intake will be via a 6.5L GM turbo diesel air cleaner ans ducting that fits this body style.There will be an intercooler with possible AlkyControl water/washer fluid injection. And the full suite of blow off and wastegate valves. Anyway I'm asking for experience from those who have run these turbo's and are satisfied or wished they would have changed to something else. Planning on sub 11psi and a little lag is no concern as the natural torque of the engine should be good to go.
Scratch the BW as too big, also starting to looking at Power Master.
Another option is a 406cid a friend is trying to sell- put the AFR's on that with a decent roller cam. But I'mwondering if fuel mileage would be killer.

 

GT45!