engine plates went with Hooker 12623HKR which moves the engine 1 1/14" forward. SB Clam Shells with V8 on Frame motor mounts.
Hedman Hedders 1 7/8" Muscle Car
if you are sticking to the 350 Turbo, no issue with the cross member as it will not be changed.
Fuel tank, use the factory tank, get a 94 Chevy Astro 4.3V6 fuel pump/ Sender, replace the pump with correct needed fuel pump, remove the locator tab for the sender, route sender to Wagon location, lock ring will hold the sender in the proper location. Use the Vette Fuel Regulator GF822 so you can run the return back to the tank and factory fuel line to the front.
I used the muscle car oil pan.
You need to plan out where you want to go, set a budget, list total parts and prices and then plan proper course forward or it is will kill you with cost.
What rear-end do you have? Gears? all will be issues to include the drive shaft if you change anything.
Just my 2 cents.