INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

I've been out of the game.New heads for 408

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Old 10-19-2017, 08:49 PM
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Default I've been out of the game.New heads for 408

I've been out of it for 8 years, whats the new heads to run on 408 or something similar. used to be 317s n/a

sounds like everyone is turbo now but ill probably keep n/a

seems like prices have come down on internals and headers etc from 8-10 years ago as well
Old 10-19-2017, 09:03 PM
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Do you want to run a stock head or like a ported head from a vendor?

243/799 heads are hard to beat for how well they perform for a stock head and would bump the compression over a 317's.

Maybe even some square port heads from a GEN 4 motor could work if you want a factory head. Something off the 6.2's.
Old 10-19-2017, 09:15 PM
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what ever is going to give more flow /power
Old 10-19-2017, 09:16 PM
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different intake with square ports?
Old 10-20-2017, 02:11 AM
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As stated, you can’t go wrong with some stock, or worked, 799/243 heads. Also, 821/823 rectangular port “LS3” heads move some serious air straight from the factory!
Old 10-20-2017, 09:24 AM
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My 408 hasnt been started yet, but....

Its the TSP/Wiseco rotating assembly. I think I paid $2800 for it? I'll have to pull the specs, but maybe the price will help you find it if you look on their site.

Its a 10.5:1 build, intended for 16psi on E, 12ish on 91.

Long story short, its got stock LS3 heads with +1mm oversized intake valves.
Old 10-20-2017, 11:48 AM
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Another good thing about the L96 engine 823 heads, is that it comes factory with inconel exhaust valves! I’m not sure on the intake valve, but they’re either stainless or inconel as well.
Old 10-20-2017, 01:11 PM
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Originally Posted by B00sted2007
Another good thing about the L96 engine 823 heads, is that it comes factory with inconel exhaust valves! I’m not sure on the intake valve, but they’re either stainless or inconel as well.
LY6 also has inconel exhaust and 823s

Intakes are solid SS. I actually have a set FS if anyone needs stock stainless LS3 size pull outs
Old 10-20-2017, 06:49 PM
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Originally Posted by arthursc2
LY6 also has inconel exhaust and 823s

Intakes are solid SS. I actually have a set FS if anyone needs stock stainless LS3 size pull outs
nice! I knew it was something along those lines. Pretty impressive GM used these materials on stock valves!
Old 10-21-2017, 10:39 AM
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Originally Posted by cmiller
I've been out of it for 8 years, whats the new heads to run on 408 or something similar. used to be 317s n/a

sounds like everyone is turbo now but ill probably keep n/a

seems like prices have come down on internals and headers etc from 8-10 years ago as well
317 were cheap and aftermarket heads were expensive in comparison. However most 408's never performed that well on the top end cause they couldn't breath.

With a 408 you need to feed that beast. I would step up to an aftermarket head. They will flow more than any ported set of factory castings.

A good exhaust system will help too.

To Quote the late John lingenfelter
"The worlds's best cam combined with a poor set of heads will produce an engine that's a dog. But bolt on a set of great heads even with a poor cam and that engine will still make great power."



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