ls1 cam and head swap to 5.3L

[mongoose90584]

My friends dad has a 2000 WS6 and he has recently purchased new heads and cam for his ls1. My question is will the cam and heads fit my 2004 5.3L silverado? The WS6 only has about 45,000 miles on it. If they do fit should I have the ls1 heads ported and polished before i put them on?

[Defunct SO]

The cam is only a little better than what you have. I would at least try and find a used LS6 cam to make the swap worth while.
The heads will slightly lower your compression, but will flow better because of the slightly larger valves.
I would find a better cam, and slightly mill the heads and do a little port work IMO.