Top End Input for my 408
07-13-2012, 01:14 PM
#1
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Top End Input for my 408 I currently have a 408 shortblock sitting unassembled in a storage unit back in the states. This will untimately going into my 1995 Impala SS once it's done. I've been looking at some cylinder head offerings from different companies, namely AFR and AI. I'm starting to lean toward AI, mainly due to the variety and results I've seen from their products. not to say AFR is a slouch by any means, I just like the options AI has available. I'm torn between pulling the L92 heads off my LQ4 thats currently in the car and getting those CNC'd by them or going back to a cathedral port head. What do you guys recommend doing? If I went back to cathedrals, i'd be swinging heavily towards AI's 230cc TFS LS2 Cylinder Head Package.
http://advancedinduction.com/LSX/AiLSx230ccTFSHead.php
Also, what cam range do you smart guys recommend for this? I'm looking for ~500+rwhp, without losing too much in the street manners department. I know the 408 will soak up a good bit of duration, I just don't want anything to insane.
The current setup is this;
1995 Impala SS
LQ4 6.0L short block
EPS 222/226 .597”/.598” 112LSA +4 advance
Untouched 69.8cc 823 heads
.054” gasket
LS3 intake
auto with Edge 3600 stall
3.73 gears
1 3/4" mid-length headers with cats
6300 rpm shift point
6500 rpm rev limiter
The new setup will be something like this
4.030 iron block
Wiseco K394X3 pistons (1.115 Comp ht, -8cc)
Callies Compstar 6.125 rods
Callies Compstar 24x Crankshaft
Clevite Bearings all around
Cometic 4.080 bore Head Gaskets (.051 comp)
~11.5:1 Comp Ratio w/63cc cylinder heads
AI 230cc TFS Cylinder Heads
FAST 102 Intake Manifold/TB
Yank or PTC 3600 stall
Any ideas or recommendations would be helpful.
http://advancedinduction.com/LSX/AiLSx230ccTFSHead.php
Also, what cam range do you smart guys recommend for this? I'm looking for ~500+rwhp, without losing too much in the street manners department. I know the 408 will soak up a good bit of duration, I just don't want anything to insane.
The current setup is this;
1995 Impala SS
LQ4 6.0L short block
EPS 222/226 .597”/.598” 112LSA +4 advance
Untouched 69.8cc 823 heads
.054” gasket
LS3 intake
auto with Edge 3600 stall
3.73 gears
1 3/4" mid-length headers with cats
6300 rpm shift point
6500 rpm rev limiter
The new setup will be something like this
4.030 iron block
Wiseco K394X3 pistons (1.115 Comp ht, -8cc)
Callies Compstar 6.125 rods
Callies Compstar 24x Crankshaft
Clevite Bearings all around
Cometic 4.080 bore Head Gaskets (.051 comp)
~11.5:1 Comp Ratio w/63cc cylinder heads
AI 230cc TFS Cylinder Heads
FAST 102 Intake Manifold/TB
Yank or PTC 3600 stall
Any ideas or recommendations would be helpful.
07-13-2012, 01:37 PM
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I had completely forgotten about Mast. I never really looked at their stuff much before, as I was turned away by the prices. I do like their square port offerings though. Thanks for making my decision tougher lol.
07-13-2012, 02:08 PM
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This is by no means a max effort build. With this car, I want as much usable torque as possible. I'm gonna need it to get this big boy moving. I want something that can fulfill daily driver duties if I wanted it to without rattling your teeth out, and still go to the track and put down some very respectable numbers. I think the AFR 245s may be a little too much for what I'm looking for.
07-13-2012, 05:52 PM
#6
I am just gonna stick my neck out here and recommend some of the PRC stuff. We have really stepped up our cylinder head line and I feel we can easily compete with any of the heads mentioned in this thread.
In my opinion if you are looking for a broad powerband with lots of torque I would look more towards a cathedral head. Generally rectangle port heads have a larger runner and valve which don't promote lots of low end power. I would take a look at our PRC 237 heads. I think they will reach your goal while keeping the low end torque you want.
http://www.texas-speed.com/p-1171-pr...der-heads.aspx
Feel free to call us or send me a PM and I will answer any question you have.
In my opinion if you are looking for a broad powerband with lots of torque I would look more towards a cathedral head. Generally rectangle port heads have a larger runner and valve which don't promote lots of low end power. I would take a look at our PRC 237 heads. I think they will reach your goal while keeping the low end torque you want.
http://www.texas-speed.com/p-1171-pr...der-heads.aspx
Feel free to call us or send me a PM and I will answer any question you have.
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07-15-2012, 11:22 AM
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Thanks Jason. I'll be looking into the PRC heads also. The purchasing of parts maybe a few months away, so right now I'm just trying to find a combination of parts that work.
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07-15-2012, 03:26 PM
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I think I may stick them on the 6.0 for the time being (once I return), run a thinner head gasket to get some compression back. I'll definitely do some before and after dyno runs also. Once I get a cam to complement them, I'll do a dyno comparison of that also. Never baselined or dyno tuned the car, everything has been street tuned by myself with the current combo, so I'm sure there are some things I could fine tune. I don't even remember how much WOT timing i'm running lol. I'll definitely be looking into this ALOT further.
