how do you hook up oil pressure guage?

[fnoblitt]

i have a 69 c10 with factory guages it had a metal oil line that hooked up to the old 6cly. now i have a new 350 v8 and the oil line looks like it needs some sort of an adapter to fit it to the block.i bought a sun oil line kit witch came with some assorted fittings and a plastic line but none of the fittings work.(they work at the block if i use the plastic line but not at the guage)does anyone have or know exactly what i need ?thanks