Seriously consider finding another slant 6- there's actually quite a few around yet. A nice 225 will make life sooo much easier for you.
That said, use the search function to find LOTS of info on a V8 swap- lots of things to be taken into consideration.
Here's one similar to your situation: 318\a904 swap in 65 barracuda
And welcome to the site!
I agree with everyone above also your 318 will need a different oil pan and a v8 steering center link. A nice healthy 225 would be a better "Budget option". By the way is that a Canadian Valiant? I can't tell by the side shot with your helper.
