I put a 351 in my 68 in 1972, I had to cut the center brace out of the hood so it would clear the air cleaner. I also had to make a oil pan by cutting the top off the289 pan and the bottom off the 351 and welding them together. The headers were another adventure….Just because the vender says 289, 302, 351 don’t make it so.. Thiswas in the early days for broncoso we had to make do. Now we have many venders making lots of parts. I have since added a1 inch body lift in an effort to Clear the air cleaner along with an ax15. There is a pan kit available through CJ and I m going to see if it fits some time this winter.. The shorty headers fit with one exception, Ihad to put a 1/2 inch spacer under the right motor mount so the right side would clear the frame and since my 351 still had big spark plug, I had to grind the notches for the plugs ( front and rear, both sides). It’s worth the trouble, more torque and potential horse power.