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408 lt1?

This is a discussion on 408 lt1? within the LT1 forums, part of the Vehicle Specific category; hey everyone i have a 96 black firebird formula ws6 and have bought a lot of parts to assemble my ...

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    408 lt1?

    hey everyone i have a 96 black firebird formula ws6 and have bought a lot of parts to assemble my 408 stroker dream.i just need to know if i need to know anything extra for the build and what kind of numbers i can expect? also want to know what size injectors i will need as well as throttle body cfm. anyone ever done this? here is a list of parts i now have.
    afr 227cc heads, 1.6 harland sharp rockers, isky tool room springs,6.0 callies rods, 4.0 lunati crank mahle pistons, edelbrock efi intake manifold, titanium valves, ati super damper, dual kickout oil pan, delteq ignition, granatelli maf, high volume oil pump and fuel pump. fuel pressure regulator. i still need some more parts for the build but just want to know how i am doin so far as well as maybe a rod length and size small base circle cam. once again any info would be greatly appreciated. i know i need 2 do a lot of machining but want to get this beast finished. thanks

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    Last edited by tomsws6; 05-27-2008 at 10:25 PM.

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    1. A 58mm Throttle Body or a Monoblade is what I'd go with;

    2. Consider nothing larger than 42LB injectors....you won't need more than that;

    3. Ditch that Granitelli MAF!!!!!!!!!.....use a stock F-body MAF;

    4. Use Impala SS head gaskets to maximize quench (still available at GM dealers);

    5. What cam you using?

    KW

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    Make sure you get that intake manifold hogged out for those heads. Those heads have alot of flow potential; no need to log jam the flow in the intake. As for pushrod length, get a length checker. Ideally, you want to check for length after the cam and lifters are in, so you make sure your rocker arm angles are correct. Make sure the valve springs are shimmed correctly for consistent installed height across all cylinders (alot of people overlook this).

    With a 408, you're stretching the factory LT1 block to its limits. Have the cylinders sonic tested to insure the block is thick enough to last with that cylinder bore and necessary clearancing for the stroker. I see no reason why a healthy 408LT1 couldnt put down 500+rwhp, NA. It will of course depend on compression, your choice of camshaft, and what your heads/intake flow.

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    intake

    im running an efi 2926 intake and wanna run 1500 cfm tb. about a 680 lift cam. as far as the block i know i will get all that stuff done. im lookn for 550rwhp with huge injectors and that intake setup. any replies?

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    Quote Originally Posted by blakdws6formula09 View Post
    .....about a 680 lift cam.....
    Is this a solid roller set-up?

    KW

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    Quote Originally Posted by 5.0THIS View Post
    ......Have the cylinders sonic tested to insure the block is thick enough to last with that cylinder bore......
    Last I checked, a 408ci = 4.030" bore.......just like a 383ci.

    The only concern is clearencing the block for the 4" stroke.....

    KW

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    it is going to be a solid roller yes and i want to flow as much fuel and air as she can take. maybe 1500cfm tb? everything p@p

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    Quote Originally Posted by KW Baraka View Post
    Last I checked, a 408ci = 4.030" bore.......just like a 383ci.

    The only concern is clearencing the block for the 4" stroke.....

    KW


    My main concern wouldnt be the bore itself, but the clearancing for the stroke. Nonetheless I would want it sonic tested.

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    5.0 is right i have 2 watch the clearance on the oil pan area of the block. how does it look so far? i also wanna run methanol injection would that help? any ideas of hp at wheels or crank if i can get max fuel and air flow? wantin at least 650 crank wit the full setup. also again how big cfm tb? i will be filling the water jackets. and like i said lookn 2 run about 680 lift cam. any help on numbers or suggestions. also any good places for machine work and p@p and price? i appreciate everyone this is my first big build and am just waitin 2get back from iraq 2 blow some vipers n bikes away lol

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    Quote Originally Posted by blakdws6formula09 View Post
    .....also again how big cfm tb......
    A Monoblade TB is as good as it gets........unless you have a custom TB built or go with a LSx TB.

    Methanol Injection? I like !

    42LB Injectors is about as much as any NA set-up is gonna need. Depending on how much methanal you're looking to inject, you can look a 60LBs injectors......but then your NA performance will be sh!tty due to an extremely rich mixture.

    My 398ci SR set-up (currently being built) is projected to push 600 to 650 HP at the crank.....that's with a monoblade TB, 42LB injectors and ported AFR 210's. So with a good tune and a reasonable selection of parts, you should be right there, too.

    KW

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    Quote Originally Posted by KW Baraka View Post
    A Monoblade TB is as good as it gets........unless you have a custom TB built or go with a LSx TB.

    Methanol Injection? I like !

    42LB Injectors is about as much as any NA set-up is gonna need. Depending on how much methanal you're looking to inject, you can look a 60LBs injectors......but then your NA performance will be sh!tty due to an extremely rich mixture.

    My 398ci SR set-up (currently being built) is projected to push 600 to 650 HP at the crank.....that's with a monoblade TB, 42LB injectors and ported AFR 210's. So with a good tune and a reasonable selection of parts, you should be right there, too.

    KW


    42 lb injectors always seem to be getting pretty high in their duty cycle at 500rwhp. Lots of people seem to have good experience with the racetronix 60 lb high impedence injectors.


    And in my personal opinion, methanol injection might help some, but I'm not sure it'd be worth having with your setup. If you had forced induction it would be a no brainer.

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    i was also thinking along the lines of at least 60lb injectors. everyone tells me to big but i was lookin at a set of accel i believe 64lb that i think will fit great. and i dont know if im going to run a monoblade or a nice huge cfm 4 barrel tb setup. any help on how much cfm? i know once again i will be using the edelbrock efi victor #2926 manifold. also should i jus run my 1.6 roller rockers or go wit 1.7 and 1.6 thanks board has added a lot of light n2 some dark areas of this build.s

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    is it dangerous to stretch it out 2 a 410 which would be .40 over? also wannna run about a 1500cfm tb and huge intake etc etc

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    Quote Originally Posted by blakdws6formula09 View Post
    is it dangerous to stretch it out 2 a 410 which would be .40 over....
    My 398ci solid roller set-up will be .040 over......so I don't see an issue with it.

    HOWEVER......unless you got a sweet deal on some 4.040", there's no particular benefit to boring that extra hundredth.

    The only reason I'm doing it is because the block I have was poorly bored to begin with and the only real fix was to bring all the cylinders to 4.040".

    KW

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    Quote Originally Posted by KW Baraka View Post
    MyHOWEVER......unless you got a sweet deal on some 4.040", there's no particular benefit to boring that extra hundredth.

    The only reason I'm doing it is because the block I have was poorly bored to begin with and the only real fix was to bring all the cylinders to 4.040".

    KW
    agreed. there really isnt anything to be gained by going 40 over instead of 30. In fact, I'd go with the smallest overbore possible to retain wall thickness.

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