68 dodge slant 6 2 v8

i have just recently bought a 4 door 68 dart 270 that has the normal slant 6 with an auto tranny. i would like to drop a 318 with a 4 speed tranny in it. i know there really isn't alot of people who do performance mods on this 4 doors but i think it would be funny as hell pulling up next the those ******* mustang guys a blowing there doors off..

my main question on this swap is do i have to replace the whole front clip or can i just drop this motor in cuz it looks like there is plenty of room.

if you can help me on this it will be greatly appreciated.