PRC LS6 heads vs PRC 5.3L heads
09-27-2009 | 10:35 PM
#1
Thread Starter
On The Tree
Joined: Dec 2008
Posts: 102
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From: San francisco, California
PRC LS6 heads vs PRC 5.3L heads Anymore comments on these heads? From the flow data, they both flow same or similar. But is there anyone who has either of these heads and is satisfied or prefers the other heads? Thanks
09-28-2009 | 10:37 AM
#3
I definitely prefer the LS6 stage 2.5 heads. The 5.3l head is a great head for the money, but if you have a little bit more $$ to spend the LS6 stage 2.5 has made more power on every test I've done so far.
Don't forget the PRC 215 heads also though. They're definitely more expensive, but still right at $2000 area. For that price you get a awesome aftermarket casting head that doesn't require aftermarket rockers.
Don't forget the PRC 215 heads also though. They're definitely more expensive, but still right at $2000 area. For that price you get a awesome aftermarket casting head that doesn't require aftermarket rockers.
__________________
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
09-28-2009 | 11:10 AM
#4
I definitely prefer the LS6 stage 2.5 heads. The 5.3l head is a great head for the money, but if you have a little bit more $$ to spend the LS6 stage 2.5 has made more power on every test I've done so far.
Don't forget the PRC 215 heads also though. They're definitely more expensive, but still right at $2000 area. For that price you get a awesome aftermarket casting head that doesn't require aftermarket rockers.
Don't forget the PRC 215 heads also though. They're definitely more expensive, but still right at $2000 area. For that price you get a awesome aftermarket casting head that doesn't require aftermarket rockers.
If I had the coin i'd get the PRC 215's but the 2.5 LS6 are really nice pieces. Jason ya'll done any side by side dyno tests with the PRC 215's vs. the other aftermarket casting pieces like the TFS 215's and the AFR 205's?
09-28-2009 | 11:14 AM
#5
It seems like most people go with the 5.3's to get a compression bump since the chamber is a little tighter than the LS6 head, but since i think TSP mills them for free I dont see why you just wouldnt get the LS6's milled to the compression you want since they flow better.
10-10-2009 | 01:30 PM
#7
It seems like most people go with the 5.3's to get a compression bump since the chamber is a little tighter than the LS6 head, but since i think TSP mills them for free I dont see why you just wouldnt get the LS6's milled to the compression you want since they flow better.
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10-10-2009 | 04:59 PM
#8
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
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From: BFE
If you go back a few years to before 2004, LS6 heads were about $1200 stock, so for budget 5.3L ported became a good alternative. With the appearance of 243 headed LS2, that reduced the price of those castings dramaticaly. Only difference on the LS2 243s you got regular stainless valves and not sodium filled.
So from then the 243s became more affordable and since they are a superior casting, they are now the head of choice.
So from then the 243s became more affordable and since they are a superior casting, they are now the head of choice.
10-11-2009 | 08:50 PM
#14
TSP can do it. They did a bunch of cam comparisons. It would be nice to see those head dynos first with a small cam 224, then a bigger 23x cam. I'm sure they have all these heads in stock.
10-12-2009 | 12:07 PM
#17
The runner lengths are different, the PRC 5.3s have a 220cc runner and the PRC LS6s have a 230cc runner. LS6 head is technically a better flowing design in stock form, but the CNC porting to both closely levels the playing field.
Quote from a similar thread with good info.
Quote from a similar thread with good info.
I would go with the 59cc LS6 & here is why...
For a long time I WOULD HAVE voted for the 5.3 heads on a street car. Mainly for what all you read about with their smaller runners & higher compression making more torque & power "under the curve". This is true to a degree. Now since then I have had some LONG talks with major head porters. The keys are runner design, runner volume, flow, velocity, & how they all work together. With stock cubes, you don't want to just start hogging out the intake and exhaust runners because the velocity will probably slow down even though you'll have great flow numbers! Typically with the bigger runners you lose some velocity which will affect your bottom end and part-throttle response. There seems to be a fine line of flow vs. velocity & good porters know this. Runner shape and the cross section of the port is more important (to a certain point) than just runner volume. A well designed smaller runner can flow better than a larger runner. Now all that being said, volume alone does not always dictate velocity. As long as the cross section is not too big, and has the proper shape, you won't lose velocity... Lets look at LS1 heads, LS6 heads & aftermarket heads.
LS1 head ~ 205cc runner & flows ~ 230cfm
LS6 head ~ 215cc runner & flows ~ 260cfm
PRC 5.3 head ~ 220cc runner & flows ~ 317cfm
PRC LS6 head ~ 230cc runner & flows ~ 316cfm
LS6 head has larger runners & flows more than a LS1 head. OK, based on the above info you prob. think it gives up a lot of velocity & low end b/c of the hogged out runners. Not the case... I makes MORE power b/c it is a better "design" & still keeps the velocity up. How can the aftermarket heads have a smaller runners & flow more??? B/C they are a MUCH better design than the LS6
There is a lot more to it than all this but I wanted to point out a few key points. I am sure I missed a lot & others can fill in the gaps.
"I think where I'm getting confused is when you throw "milling" into the mix. By milling the heads, it helps increase compression even more, hence increasing the velocity of movement of air through the heads (please correct me if I'm wrong on this). Can you guys give me a simple explanation as to how this is accomplished?"
No, by milling the heads you ^ compression which = more torque/power.
For a long time I WOULD HAVE voted for the 5.3 heads on a street car. Mainly for what all you read about with their smaller runners & higher compression making more torque & power "under the curve". This is true to a degree. Now since then I have had some LONG talks with major head porters. The keys are runner design, runner volume, flow, velocity, & how they all work together. With stock cubes, you don't want to just start hogging out the intake and exhaust runners because the velocity will probably slow down even though you'll have great flow numbers! Typically with the bigger runners you lose some velocity which will affect your bottom end and part-throttle response. There seems to be a fine line of flow vs. velocity & good porters know this. Runner shape and the cross section of the port is more important (to a certain point) than just runner volume. A well designed smaller runner can flow better than a larger runner. Now all that being said, volume alone does not always dictate velocity. As long as the cross section is not too big, and has the proper shape, you won't lose velocity... Lets look at LS1 heads, LS6 heads & aftermarket heads.
LS1 head ~ 205cc runner & flows ~ 230cfm
LS6 head ~ 215cc runner & flows ~ 260cfm
PRC 5.3 head ~ 220cc runner & flows ~ 317cfm
PRC LS6 head ~ 230cc runner & flows ~ 316cfm
LS6 head has larger runners & flows more than a LS1 head. OK, based on the above info you prob. think it gives up a lot of velocity & low end b/c of the hogged out runners. Not the case... I makes MORE power b/c it is a better "design" & still keeps the velocity up. How can the aftermarket heads have a smaller runners & flow more??? B/C they are a MUCH better design than the LS6
There is a lot more to it than all this but I wanted to point out a few key points. I am sure I missed a lot & others can fill in the gaps.
"I think where I'm getting confused is when you throw "milling" into the mix. By milling the heads, it helps increase compression even more, hence increasing the velocity of movement of air through the heads (please correct me if I'm wrong on this). Can you guys give me a simple explanation as to how this is accomplished?"
No, by milling the heads you ^ compression which = more torque/power.
10-12-2009 | 09:10 PM
#19
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The runner lengths are different, the PRC 5.3s have a 220cc runner and the PRC LS6s have a 230cc runner. LS6 head is technically a better flowing design in stock form, but the CNC porting to both closely levels the playing field.
Quote from a similar thread with good info.
Quote from a similar thread with good info.