Fuel pump options: Have you moved your tank out of your cab yet? If not, an inline pump will probably be your only off the shelf choice. Numerous brands avaialble from Jegs, Summit or one of our forum sponsors I'm sure. If you have moved your tank out of the cab, you may be able to sink an in-tank pump (quieter, more reliable) or use the inline.

Speedo: If you are planning on retaining your mechanical drive speedo, a cable-x box or a tranny tailshaft modification to add a speedo drive gear will be neccessary. If you are planning on swapping out your gauges to a custom panel anyway, speedo hookup is as simple as conecting a wire on the electronic versions available now.

I did the tailshaft mod on my Camaro swap to add the mechanical drive and original speedo, but on my truck I swapped out all my gauges for electric rather than mechanical easing the hookup problems.

Radiator: LSx engines are not inherently difficult to cool, so if you have a radiator in good shape that was doing a trouble free job and adequately cooling a Gen I V-8, it will cool your LSx engine. You'll have to play with radiator hose sizes but that's all part of the fun isn't it?