I'm wanting to add some cubes to my 79 F100. It has a 302 and C6 right now. I would like to put in a 400. Has anyone done this swap? If so, what all has to be changed? Do I need beefier springs? What about rad? I know I have to change the tranny. Is this worth it, or do I need to drop in a 351W and forget it? Thanks in advance for help.

Scott
79_Effie

 

Basicly you will need mounts for the 400, the mount supports in your truck now will be fine, your C6 will not bolt up to the 400, but you can sell it for a very good price, as small block C6s are hard to come by, your springs will probably be OK, you can get away with installing overload shocks on the front, these are the ones with springs around them, you will also need brackets for accessories you have as nothing from a 302 will swap to a 400.
Your idea on a 351W would be easier, as it will bolt right up to your mounts and trans.