Wheel size (offset) on a lowered '68 C20 ??

[KevinK7]

Just want to run this past the experts to see if I'm on track with regard to wheel offset for my planned setup.

The truck: '68 C20 Utility bed (396 BB, 4sp)

Lowering: I plan on going with Performance Online (POL) 2 1/2" front (8-lug) drop spindles (with Disc brake conversion) along with 4" drop coils in the rear (hence 2.5/4 drop).

Wheels: I plan to go with with 17x8" ('05 OEM Dodge) aluminum wheels with a 5.7" backspace (8"/2 + 1.7" offset=5.7 BS).

Since factory BS was I think 4.5"(16x6.5 wheels), I believe I will need to make-up 1.2" hence thinking I might need to ADD about 1" spacers.
POL notes that the (disc) spindles bring the front wheels out 3/4" (0.75").

Based on the above, what is your take on my need for spacers up front/rear?
I am thinking I might be OK up front with no spacers, but need to add (1"?) spacers in the rear (to line up with the fronts)?


As for...
Tires: Going to go with whatever fills the wheelwells best with the lowering and wheels above. Thinking in the range of
275-55-17 (6.0SideWall 10.8Width 28.9Dia) or
275/60-17 (6.5SideWall 10.8Wide 30Dia)


Note: The truck will otherwise maintain complete stock (C20) equipment. With the exception of course of whatever is necessary to update with the lowering (ie. shock relocation brackets, adj. panhard, etc)