Engine Swap 2003 2.7

[Muskoka Minute]

Hi Guys

I know this topic has been talked about before.

We have a 2003 2.7 with a auto transmission.

We have a 2001 2.7 that we would like to put in it.

I have been told 2 different things.

1.Will Work
(We will have to change everything as if it was a long block)
(fuel rails, wiring harness, plenums, throttle body etc)
Then it will work

2. It will not work at all
(they have a different timing system and heads)

Which one is correct.

Hope someone knows the infinitive answer.

Thanks Bart