Hi GPNX,
You could go Nylon the whole way but I used the factory fuel line where possible. I welded Dorman fuel line connectors onto the sending unit (supply and return) and where the factory rubber hose normally connects to the supply line above the rear axle hump. Some guys use steel compression fittings. My L92 has a single feed fuel rail set up so I used Dorman nylon replacement lines between a C5 corvette regulator and the supply line. The regulator is mounted behind the VIN 9 442 heat shield. Up front, the nylon fuel line connects to the factory steel fuel line at the front passenger side body mount. Dorman also selIs plastic fittings but I used the nice stainless fittings you can find on mid 90's Cadillac & Aurora Northstars. To the untrained eye, the set up looks like it came from the factory that way. I had a hard time finding good 3/8 nylon supply line in the yard so decided to buy new from Dorman.
Here are a few links that might help:
http://www.dormanproducts.com/gsear...ine-connectors-retainers&parttype=Fuel%20Line
https://www.summitracing.com/oh/sea...=Ascending&keyword=19239926&retaillocation=oh
