Solve with Wire harness?

[lost_66]

My 78 GMC serria engine is line 6 292CI i was going pull
line 6 out and put other v-8 in but wire harness is short
than v-8 so i went junk yard pull 1980 chevy pickup wire harness
with v-8 and i hope wire harness will work bolt on my fuse box
on front cab wall. because 1980 fuse box has plastic plugs
but my 78 fuse box has glass fuse but plug from wire harness
look same? has anyone had expierence with it??? pls let
me know..