We want to buy a new engine for an F150. We'd like to price new &
used. It's a 1991 5.0 liter, 302. What I'd like from Google is a list
of sites with engines like this for sale - that's the priority, and
another list, secondary, with information about replacing an engine.

Thank you

I would suggest going to NAPA (http://www.napaonline.com) and buy a
manual specific to your vehicle. Read the part about removing and
replacing the motor. If what is being described makes sense to you,
buy a rebuilt engine through NAPA and install it. Be careful. This is
a heavy block of steel and you'll need jack stands, blocks of wood to
support the transmission, and an engine hoist. Read all of the
instructions in the manual before starting this. Do the work inside a
garage or covered area. Have a backup vehicle available to shag parts
and tools with. It will take twice as long as you or the manual says
it will. Good luck.