Wow, the new boss 302! You the boss, boss! Have you done any measuring to see if it'll fit? I'd love to see the swap and hope it works out for you.
Hope the plans work out for you. I'll agree with these guys if you got a steady job you like, keep it if you can. Much better to stay where you are and enjoy the job you have, than to move for the money only to end up with an unstable job that you hate. I kinda have the opposite problem, a stable job that pays well, but I hate it. All the jobs that I think I would like more pay less and aren't near as stable. With the house payment and car payment I can't afford to make less.
I'll also warn not to bite off too much. A roof over your head is more important than 3 vehicles, or a 302 boss swap, with no place to park them. I've had a few friends make the jump into home ownership and try to keep playing like they lived with mom and dad, they found out the hard way that priorities need to change a little. I was fortunate enough to figure it out real quick and put the toys on the back burner until I got settled into things. Then I totaled that toy, but that's beside the point. Now I'm back playing with the toys as time and finances allow, while they are back living with their parents or in-laws. Not saying don't get the 302, just know that it can be stored until you get other priorities in order.
EDIT: Sorry if I'm preaching to the choir, don't know your experiences in life. You may have already been through this before, I don't know. I do know that if I could have warned those friends I would have done it, so I'm trying to do the same for you.