questions

[pkj]

first have truck down to frame and noticed rad is a 3 core in very good shape. i will be using a 400 sbc mild build. keep it or spend more money on 4 core?
second i saw a pic of a truck that the side markers caught my eye. they had a billet or chrome trim ring with 2 vertical dividers. looked neat anyone know about these?
third have a muncie hanging on back of motor with no crossmember under it. its okay now, but when i stick that 400 in, i think i need to do something. i can make something. or is their somthing that will just bolt in?
forth after paintig frame what is best order to put body parts back on?
cab, inner fenders, outer fenders, core support, gravel guard, grill, cowl,
all parts are edge and back painted so i hope to keep scratching down, will use lots of tape.
last question, new door shells hang and adjust first or put all guts in laying flat, off truck?
alot of questions i know, but thanks ahead. pkj