Jantzer98SS

iTrader: (54)

I'm going to pull the Stage I's in favor of a new setup. I'm not quite sure which way to go. I hear good things about the 6.0L heads, but haven't had the chance to play around with them. And I KNOW the 5.3 heads will make more power than 5.7 heads because of the compression. Plus the 6.0L heads would be less porting work for me. <img src="gr_stretch.gif" border="0">

Now will the added low-mid lift flow more than offset for the increase in compression? What are your opinions? The intake manifold in this case shouldn't restrict the increase in low-mid lift flow either. Hmmmmm.....

I think we're seeing some pretty good dyno numbers lately with the LS6 heads...

VINCE

iTrader: (1)

Scott why dont you do a set of 6.0L heads and find a test mule I mean person to try them out? That would be a good comparison.. Whichever one they like they could pay for that head.. <img src="gr_stretch.gif" border="0"> Plus, labor of course.

CHRISPY

I would go with the 5.3L heads and see what you can get out of them <img src="gr_stretch.gif" border="0">
Cheers,
Chris

Jantzer98SS

iTrader: (54)

Blackhawk2000:

Spill the beans here. What are the two castings and which is supposedly better?

I'm leaning toward the 6.0L heads now. My plan is 2.055 1.60 Ferrea's and milling around .035 -.040 to get the compression back up. This way I can increase compression over STOCK, yet not so high that I have to worry about fuel/KR. After looking at the port shape on the 6.0's, I love em. The intake port floor is shaped WAY different and the short side is nice. One additional comment, the 6.0 valve seat itself is shaped differently than the 5.3. I think if I go the 6.0 route I might play around with the stock seats and see what the flow does. Then go with the aftermarket seats.

Can anybody recommend a good aftermarket valve seat? I figure I might as well go all out now, because a big motor is definately in the future.

Speed Demon

I used stock intake valves and REV 1.57 exaust valves on the stage I's in my car. Only because I was in school and couldn't afford the intakes. What I know now is that the valve shapes make a HUGE difference in flow. You must get a good valve job and good valves.

Chris ARE 360

I know what you're saying. But wouldn't it make sense to go with the considerably better flowing heads? We're talking 20-25 cfm low-mid lift flow advantage. From .050 to .400 that adds up to a lot of flow if you catch my drift.

Does anybody have flow numbers of recently ported LS6 heads compared to LS1? I know about the ARE test way back when.

Terry Burger

iTrader: (4)

Guys have done 6.0l heads and don't seem to come up with any more power than the 5.3l guys. I'd just pick whatever is easier. I think you'll have a hard time getting the CR down on 6.0l heads.

Speed Demon

iTrader: (14)

I say go with the 6.0's. I have already started on mine.

Since you are more experienced than me I would like to compare notes and results.

Let us know what you decide to go with.

Also, did you use stock vavles on your previous heads or aftermarket? Any idea how much HP or flow aftermarket valves are worth on home ported heads?

blackhawk2000

The 6.0's are the best heads from the factory. This is from a GM engineer. There are 2 different casting numbers, and 1 flows better than the other*. They are only down on compression compared to an LS6 head, and only slightly if at all on an 5.7 head.

*Better flow may be due to the different casting process' between the 2, and may not matter if porting.

99 Black Bird T/A

iTrader: (4)

There's a member on this site, Sporadic I think, that has 6.0 Heads and a B1 by TEA. The car made 420 rwhp with the LS1 intake. I'm impressed. I think the mid lift advantage of the 6.0 heads works pretty well with the old LS1 intake...of course the LS6 intake probably better still.

My .02 worth is try the 6.0 heads. I think the 01 and up castings are different than the older 99 and back 6.0 castings.

Thought you might want to see this too if you haven't:

[quote]Originally posted by wizkid:
<strong>Sporadic, has 6.0 L truck heads. He said they were milled 0.030" with a resulting combustion chamber of 63cc. That makes for 10.6:1 static compression if everything remains the same as stock (minus the heads).

ERic</strong><hr></blockquote>

[ February 16, 2002: Message edited by: 99 Black Bird T/A ]</p>

blackhawk2000

Let me talk to my guy, and I'll get the numbers for you.

Basically 2 suppliers made some early castings. 1 of them used a slightly different process, and had better results. My guy thinks it's probably just the casting texture, and he doesn't think there are any changes in the design.

I also know something else about the heads, but I'm not sure if I'm allowed to say anything about them yet <img src="gr_images/icons/wink.gif" border="0">