picking a set of heads
12-17-2007, 08:36 PM
#2
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thats a hard pick ported 5.3 are a good head flow extremly well and have good compresion but im preety impressed with the 243s i think they are an awsome budget head i run stock 243s and the same cam and make 430hp 410 trq so id say go 243s i just wouldnt mil them and run a 40 mil gasket
12-17-2007, 11:22 PM
#4
LS6 CNC Ported is what I would choose. THe 5.3 heads will give you more compression if I remember right but you might not be able to clear the piston without flycutting them maybe because of the 595 598 lift. I dont know for sure but you can ask Texas Speed when you order them.
12-18-2007, 12:17 AM
#5
Lift has nothing to do with it! The duration is the reason for having to flycut. I dont believe you'll have a problem w/ the torquer 2.
Evans72 was correct about 1 thing..... Call TSP and ask John he'll know for sure.
The 5.3s are a better flowing head! John told me if I was going F/I go ls6 if N/A then go 5.3s.
Evans72 was correct about 1 thing..... Call TSP and ask John he'll know for sure.
The 5.3s are a better flowing head! John told me if I was going F/I go ls6 if N/A then go 5.3s.
12-18-2007, 02:39 AM
#6
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Lift has nothing to do with it! The duration is the reason for having to flycut. I dont believe you'll have a problem w/ the torquer 2.
Lift has little to do with it at those duratioons, it is the valve events you have to watch for as well
Evans72 was correct about 1 thing..... Call TSP and ask John he'll know for sure.
Their 5.3L stage 2.5 will clear that cam with no issues.\
The 5.3s are a better flowing head! John told me if I was going F/I go ls6 if N/A then go 5.3s.
That is not so true, 5.3L bump compression because of smaller chambers, ported both castings have almost equal capabilities, 243 outdoing the 5.3s as the valves get bigger.
243s have bigger runners (can range from 227>235 in some cases)
5.3L have ~ 220cc runner in general and have a tad more velocity depending on the CNC program
I think you might have missunderstood John, because for FI you'll need much bigger chambers (like 72cc) to reduce compression.
Point being fully ported to a stage 3 (2.08/1.6) valves a 243 will outflow the 5.3L
So, both heads have their benefits depending on the application at hand, cam used and compression desired as well as size of motor.
Lift has little to do with it at those duratioons, it is the valve events you have to watch for as well
Evans72 was correct about 1 thing..... Call TSP and ask John he'll know for sure.
Their 5.3L stage 2.5 will clear that cam with no issues.\
The 5.3s are a better flowing head! John told me if I was going F/I go ls6 if N/A then go 5.3s.
That is not so true, 5.3L bump compression because of smaller chambers, ported both castings have almost equal capabilities, 243 outdoing the 5.3s as the valves get bigger.
243s have bigger runners (can range from 227>235 in some cases)
5.3L have ~ 220cc runner in general and have a tad more velocity depending on the CNC program
I think you might have missunderstood John, because for FI you'll need much bigger chambers (like 72cc) to reduce compression.
Point being fully ported to a stage 3 (2.08/1.6) valves a 243 will outflow the 5.3L
So, both heads have their benefits depending on the application at hand, cam used and compression desired as well as size of motor.
12-18-2007, 12:44 PM
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I have a set of PRC stage 2.5 5.3L heads on mine. My car is mostly driven on the street. I chose these because I was told the LS6 heads have almost too large intake runner size when it comes to stock cubes. Mine is very snappy, lots of power under the curve. That is where you want it on the street. I am by all means not an expert, and Predator knows his **** when It comes to heads and cams. just sharing my experience with mine.