I am thinking about changing over from my Weiand LS1 intake to a LS6 intake and was wondering if I would be gaining anything or if I would even notice the changeover

 

Should be no difference. Same power level, but yours could be ported and make more..

 

If it's the Weiand I'm thinking of, it's metal. And that's bad because they heat soak something terrible.

From the info I saw, the Weiland was a little better down low, and the LS6 was much better up top and made more power. However, after extended use, the Weiland dropped below LS6 performance at any RPM.

 

Yea I was afraid of that and you are right it is the polished metal looking one and it is considerably heavier than the stock one

 

I read that the Weiand makes more power than the LS6 manifold. I wish a could remember what magazine did the test of all the LS1 manifolds that would help.

 

We bolted a Weiand/Lingenfelter aluminum intake manifold onto a stock 1999 Pontiac Trans-Am WS6, and we were rewarded with 22 more RWHP on our Mustang Chassis Dynamometer at Exotic performance Plus.

This is on EPP's website, not going to argue that the Weiand is better but I don't think your going to notice a difference with a LS6 manifold.

 

I had the unfortunate experience of reading through some pissing match threat about ls6 vs ls2.

However,
There was a least some good info in there.

The Weiland is in there too. On average with a stock TB it produced 16 hp and 16 tq less than the LS6 at peak numbers. If you have an LS6, I certainly wouldn't upgrade unless you were looking for a show car (can polish the Weiland).

http://www.tpis.com/index.php?module=2_17_06

 

I'm a little suspect of the tpis article, they used stock injectors at 500+ hp? EPP says they picked up 22 rwhp over a stock LS1 manifold, the tpis article shows it making less hp than the LS1 manifold.

I don't know.