bare unassembled gmpp cnc heads
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Teching In
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bare unassembled gmpp cnc heads First time post and new to the lsx world. I have gotten a lot of great info from this site. I am building a 408 ls and it's time to pick heads. So many opinions out there. But I was wondering if anyone knows where I can purchase a set of bare unassembled set of gmpp cnc heads. The ones I am looking for are the rectangle ls3 style . Any help would be great.
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They are OK heads, but others do a better job. Check with Texas speed and Performance for their CNC LS3 heads. They flow more with a smaller port volume, which means better throttle response and torque under the curve. The GMPP design is old. Better porting programs have surfaced since then
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Thanks, for the reply. I was looking at the new afr 260 but when I ran that by my engine builder he said those are alitte too big for a 408 and he usually uses those on 416s and bigger. He recommended the gmpp cnc heads. But I haven't purchased anything yet and I knew I would get some good advice in here.
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Yeah TSP isn't the only one, but one of the best. Also look at Total Engine Airflow, Katech, Frankenstein, etc. Look at the sponsor list for this site. There are a bunch of head porters.
Been running the cnc LS3s a few yrs, motor made 513whp 482wtq after TDs & upgraded pushrods to 3/8! Really needs the intake ported, which I plan on doing soon! Been a beast, beat boosted cars, SBC cars on spray so everyone in town thinks the car is being sprayed lol! Not yet!
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Thanks, for the reply. I was looking at the new afr 260 but when I ran that by my engine builder he said those are alitte too big for a 408 and he usually uses those on 416s and bigger. He recommended the gmpp cnc heads. But I haven't purchased anything yet and I knew I would get some good advice in here.
AFR LS3 260 CC port is smaller then the GM LS 3 Ports especially
The CNC version. AFR 260s would be great on a 408" or the
TFS LS3 255s also. For a street engine I would run MMS 235s
More strip/track oriented AFR 260s absolutely!
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Teching In
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Navyblue210 Thanks for the response also. I think what the engine builder is thinking is that with my goals the gmpp cnc head will work and afr 260 head is overkill. My goal is 600 fly wheel hp plus 150 shot. It's a 50/50 strip street car. I want to cruise some as well. But with my way of thinking was that the 260 afrs would get me there easier. But this builder does a lot of lsx motors and he says he has a single turbo 408ls that pushes 1000hp with the gmpp cnc heads and it is very steetable.
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My point above was that there are other heads that will do a better job than the GMPP heads at a better price, AND give better low and mid range performance. The ports on the GM heads are so big that they will kill the low end, compared to others. Plus, they don't flow as well as the others mentioned.
My point above was that there are other heads that will do a better job than the GMPP heads at a better price, AND give better low and mid range performance. The ports on the GM heads are so big that they will kill the low end, compared to others. Plus, they don't flow as well as the others mentioned.
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The GM ones are already ported "more" than most, with larger volume ports that flow LESS than most others. In other words, they are less efficient than most others, and are not much cheaper. The OP is looking for bare heads, so the valve question does not enter into this conversation. With bare heads you get your valves and other hardware from whomever you want
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G Astma I checked out total engine airflow and frankenstein heads and I noticed they both offer a base ls3 head that they work over and stamp their name on. Do those heads still have the large ports you mentioned earlier? Are the heads offered by two companies that different from the gmpp cnc heads. Flow numbers are comparable. I know flow numbers isn't everything and port size plays a big part. So I guess my question is what makes frankenstein or tea heads better since they are ls3 heads to start with.
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AFR,TFS, & MAST LS3 Heads are all available bare from Summit, any of these
Will perform better than the GM CNC LS3 Heads even ported by quality vendors.
Smaller Ports, higher velocity & flow @ low,mid, & high lifts, means more power
and better drive ability with smaller cams and they all have .750" deck thickness
for greater strength with N2O or boost compared to factory castings.
Just saying you get what you pay for and Cylinder Heads are the Stars in any
Build with cam, Intake & the rest acting as the important BUT Supporting
Cast members.
Good Luck
Will perform better than the GM CNC LS3 Heads even ported by quality vendors.
Smaller Ports, higher velocity & flow @ low,mid, & high lifts, means more power
and better drive ability with smaller cams and they all have .750" deck thickness
for greater strength with N2O or boost compared to factory castings.
Just saying you get what you pay for and Cylinder Heads are the Stars in any
Build with cam, Intake & the rest acting as the important BUT Supporting
Cast members.
Good Luck
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Is you looking at LS3 heads just because of the flow numbers?
I'm not go play peek a boo like others do. If this is a pump gas all motor setup I would look into another option for cylinder heads. Plenty of 408ci cars (f-body) on board here struggling to run 10s on motor with CNC LS3 heads. Most crack a low 11 and very few run high 10s. I'm also referring to 6 speed cars which is harder to get down the track more efficiently.
I'm not go play peek a boo like others do. If this is a pump gas all motor setup I would look into another option for cylinder heads. Plenty of 408ci cars (f-body) on board here struggling to run 10s on motor with CNC LS3 heads. Most crack a low 11 and very few run high 10s. I'm also referring to 6 speed cars which is harder to get down the track more efficiently.
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Keep factory heads only thing is they were ported by GM. Get a good cam and done with a 408 guys are making 550 with hyd roller stuff with factory heads and stock cubes the added stroke only helps TQ. You only asked for 600 fwhp I’m thinking more like 615-620ish. Cam and compression with a nice stock intake with the trick radius rod and you’ve got a nice killer with a 6800 Peak Rpm, intake dependent, Super Vic....CID.
No need to go out and buy overkill for heads most guys are saying this only because TQ is normally higher under the rpm curve with aftermarket heads. If you cam it correctly the extra $$$ spent is null and Void. If purchasing a head don’t go back to BS Ls3 heads go with a better product in Ls7 heads if your buying aftermarket. That’s just on runner location as some will get on here with the it has s 12 degree valve angle Yet still has a crappy Ls3 low runner port design. If you do it correctly you can have nos with factory heads as long as the tunes right.
No need to go out and buy overkill for heads most guys are saying this only because TQ is normally higher under the rpm curve with aftermarket heads. If you cam it correctly the extra $$$ spent is null and Void. If purchasing a head don’t go back to BS Ls3 heads go with a better product in Ls7 heads if your buying aftermarket. That’s just on runner location as some will get on here with the it has s 12 degree valve angle Yet still has a crappy Ls3 low runner port design. If you do it correctly you can have nos with factory heads as long as the tunes right.
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Nos and stock cubes Ls3 and factory heads with a Hot shot!
416 NA Factory Ls3 heads and block.
Cam it correctly with nice compression. Your cam will be in the 232-238 range for intake duration. Build it for your application for intake choice.
416 NA Factory Ls3 heads and block.
Cam it correctly with nice compression. Your cam will be in the 232-238 range for intake duration. Build it for your application for intake choice.
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Foxkiller- Just noticed your target horsepower is 600 motor. The stock LS3 heads are good for close to 600HP UNPORTED. IF you are looking for more than that, then as said above, just about anybody's ported LS3 heads will outperform the GMPP ported LS3 heads.
Last edited by G Atsma; Oct 8, 2017 at 11:53 PM.