Web-site and Engine question

Hey, I got a question about this site... is really the engine one I can switch with mine? http://www.factoryrebuiltengines.com/engines/
And witch one would be the best and easiest to install into my 1991 RS TBI?

Plz somone anyone answer my question PLZ!

Dude you can easily swap out any small block chevrolet engine with out much problem and a big block with some minor fabrications.