1993 ford f150 engine work

Hello just bought a truck 1993 ford
f150 with 116k on it frame and body
is in great shape almost mint. Took a
look at it buy said needs valves make
noise. I started it up hardly any kind of
noise. Started smoking a little in the
instake box. 400 bucks I took it. She
miss fires a little on take off at lower
rpms. Drove it home 30 miles and she
hardly smoked. Looking oil out of the
oil cap pov tube something of sort.
Smoking out of there too. So im just
assuming needs new rings. How hard
is it to tear heads off and bottom end
and replace the rings and rough est
on price? 116k should I replace the
crank bearings also? And whats a
good brand to go with? Any kind of
info would help debating buying a 302
or just some rings and bearings and
gaskets. Moto is stick with your motor  
id be doing all if not majority of the
work I have the tools and skills to do
so.