1964 Rambler American engine swap

So my son and I had a blast in our 1964 American 330 this summer...going to car shows pretty much every week, and afterwards, just cruising around...but the valves are rattling, its smoking pretty bad, and leaking oil in a couple places, plus the tranny is leaking, and whines when you pull out, so we are seriously considering replacing the 195.6 with a bigger engine...hopefully one that we can still find parts for. My question is...what would come closest to bolting up to the motor mounts? What engine would be less work and less cost to drop in this thing? I dont know if I can find an AMC engine, and if I did, I dont know if I could rebuild it. I havent done a rebuild since I was a much younger man, and even then I had my dad to help.
I think a rebuild kit for the 196 is over 1000 bucks, and thats way out of my budget for just the kit. Will a Ford motor work? Chevy? Any suggestions would be greatly appreciated. I dont intend it to be a hot rod, but I would like a small V8, maybe like a 289 or 302.

Why not a 290-304 AMC V8 ?

I would look for a good used replacement. If you are not mechanically minded, a drivetrain upgrade might be too much. No offense meant! 

a v8 swap is not that hard if you can find a 290 304 or a 360 you just need a 66-69 v8 crossmember or a 6cly one with the bulltear of the same years because the bulltear don't work on the 64-65 crossmember as for tran if you go a 290 your stuck with the borg warner trans you did not say if it was auto or Manuel if you go 304-360 then you can use a 727 trans it much easier to find a 360 and 304 than a 290 but yes 350 swap is a doable swap if you ook in the franken rambler section you might find some info my 65 220 has a 290 with the t10 tran very fun to drive   

oh yes sorry I forgot about the newer cars