To clarify things in my mind - your truck is/was an '88 with a second gen front clip? And now you're using an '89 cab but putting your '88 dash back in?
That is going to be a treat. The dash, pedal assembly, and steering column mounts are all very different between 1st and 2nd gen trucks. I did the opposite, I put a '92 dash/pedals/column/HVAC ductwork into my '88. If you haven't hauled off your old cab yet, don't, it REALLY helps to have basically the firewall section to compare and rob sections from. I had to use a lot of stuff from a donor cab I had on hand... check out my build thread, starting at post #60 for an idea what you're up against, it's basically what I did but in reverse.
I will post up more info concerning shocks, drop radius arm bracket, sway bar, springs, and bump stops once I get everything cleaned up. This truck is unbelievably filthy underneath and everything is getting run through the parts washer before I can take good pics.
www.therangerstation.com