68 to LS1 motor swap Questions.. HELP plz !!

[Thrmn8r]

Ok.. been doing body work for a long time.. almost done, but getting close to dealing with other issues.
Have a few questions I can't seem to find answers on.
Starting with a 1968 GMC..
Installing a 2002 5.3L Vortec & 4L60E Tranny.
Radiator..
Need to get a new one.. do I order a 68 like orig, or a 2002 and modify mounts?
Will upper and lower radiator hose fit if I use 68 orig style radiator.
The O.D. of water inlet / outlets look like they do not match up.

Power Steering...
Using pump that came with 2002 motor.. but using 1972 Power steering box,
What, and where do I find the proper fittings to match up the new hose to old style steering box ?

Fuel...
I ditched the in-cab tank and welded up the hole. Want a under bed style tank, .. bought the kit from Classic Truck Parts, and already returned it a week later.
It is too deep for a lowered truck. Too deep / low to the ground for my style.
Is there a shallower one ??
Fuel pump.. which one / system is best ?
This motor has a cable system.. do I need to build modify something to work ??

Transmission...
Gonna use the 4L60e that came with motor.
Do ya have to create a shift linkage set up to work with column shift ?
How do you address overdrive ?? How do you engage it if there is no button on column shift ?
Speedo ?? see next item !!

Guages...
Do / can you use stock gauges ?
Will fuel gauge hook up normally ?
Speedometer ?
Oil pressure ?
Ignition switch ???

Do you need a check engine light on dash ??

These are all the questions I know about.. I am sure I will find more.

You all helped me big time on the engine mounts, and the header situation, and I greatly appreciate it.
I am trying to get all the body work done so I can get it painted, and then tackle all of the above fun times I have in the future !!!

Thanks