Ok guys i need some help here. I've got an 03 sierra with the lm7 5.3 motor. I have just recently found that my heads are leaking coolant.(common problem with 5.3l stock heads). I am wanting to upgrade the heads. I was told a good setup would be either the ls1 heads and cam or the ls6 heads and cam. But i also was told that the ls6 setup has a problem with shrouding the valves. any info or suggestions would be great. I need to know asap so that the problem can be fixed before other damage is caused. thanks

 

welcome to performance trucks, I have never heard that the head leaking is common, not at all. Swapping to the LS6 heads will lower compression, losing you power unless you mill them.

 

I've never heard of that either. Someone is bullshitting you.

 

yeah the coolant leak is a common problem on the 03's to i think the 04-05's maybe. is has something to do with the way one of the bolt holes is machined. Its actually a week spot and will crack. I work at a dealership and have seen is several times. so what are the best heads to go with?

 

Texas-speed.com actually sells a 5.3 head very often as a performance part on LS1 cars. I would go with a set of their heads and cam packages.

http://texas-speed.com/shop/item.asp