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402 or 408?

This is a discussion on 402 or 408? within the General Help forums, part of the LSx Technical Help Section category; which wud be better on a street car 402 with 200 shot or 408 with 200 shot and with what ...

  1. #1
    Member blackls1ta's Avatar
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    402 or 408?

    which wud be better on a street car 402 with 200 shot or 408 with 200 shot and with what heads work the best on either,thinkin of 1 of these engines instead of heads,cam ls1,thanks for any help.

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    Slow'er'Ass Mr. Luos's Avatar
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    You will want heads and cam for the 402/408 as well.

    408 will be an iron block.
    402 will most likely be an aluminum block.
    Either will do great.
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    Member blackls1ta's Avatar
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    any other speed shops besides tsp that sells these engine kits?

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    Slow'er'Ass Mr. Luos's Avatar
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    Check out our sponsors.
    Plenty of shops sell them.

    Remember, $3700 or so is only the shortblock. No heads, no cam, no lifters, no pan, no covers, etc...

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    Member blackls1ta's Avatar
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    Quote Originally Posted by Mr. Luos View Post
    Check out our sponsors.
    Plenty of shops sell them.

    Remember, $3700 or so is only the shortblock. No heads, no cam, no lifters, no pan, no covers, etc...
    ok cool im gonna run the stock cubed ls1 while i build the 402 so maybe mid summer be ready to drop in,thanks for help

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    Slow'er'Ass Mr. Luos's Avatar
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    Quote Originally Posted by blackls1ta View Post
    ok cool im gonna run the stock cubed ls1 while i build the 402 so maybe mid summer be ready to drop in,thanks for help
    Not a problem.

    Feel free to PM me questions when the time comes if you have any.

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    Senior Member mrr23's Avatar
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    Quote Originally Posted by Mr. Luos View Post
    You will want heads and cam for the 402/408 as well.

    408 will be an iron block.
    402 will most likely be an aluminum block.
    Either will do great.
    the difference between a 402 and 408 is the bore is cut .030 over

    402 = 4" bore and 4" stroke
    408 is 4.030" bore and 4" stroke.

  8. #8
    Moderator Firebirdjones's Avatar
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    Mrr23 is correct, they can both be built from the cast iron block. So long as you buy the new cast iron block from GM (only $600) it wouldn't need bored,,shove the 4 inch stroke crank in and you have your 402.

    This is the method I would prefer for the simple reason that there is .030 left in there,,,,,,,it would allow another rebuild on down the road when the time comes and be cheaper in the long run,,,,.

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    Member blackls1ta's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    Mrr23 is correct, they can both be built from the cast iron block. So long as you buy the new cast iron block from GM (only $600) it wouldn't need bored,,shove the 4 inch stroke crank in and you have your 402.

    This is the method I would prefer for the simple reason that there is .030 left in there,,,,,,,it would allow another rebuild on down the road when the time comes and be cheaper in the long run,,,,.
    good info,thanks

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    Quote Originally Posted by blackls1ta View Post
    which wud be better on a street car 402 with 200 shot or 408 with 200 shot and with what heads work the best on either,thinkin of 1 of these engines instead of heads,cam ls1,thanks for any help.
    to be honest, if ure looking for a nasty street car you can stick with ur ls1, add h/c package and it can be pretty freakin nasty on the street. when you get into a motor swap its going to be so much hassle/time and MONEY. i personally wouldnt swap my ls1 out for a 402 or 408 unless i was looking to make my car a more track car. of coarse dont get me wrong, it would be sick to have that on the street, but its alotta money to shell out when you've got a good motor under your hood right now... just my two cents...

    ps- the guys are right depending on what block you get, what motor package (whether it comes with good heads/doesnt ect..) you're more than likely going to be swaping out the heads with a crate motor, also you're going to need a cam with a new motor too. *like what was said above* weight your options before u buy a crate motor, spend 8 grand and see that you need to spend another 7. if i were you i'd throw h/c on the ls1 and run mid 11s all day for my street car.

  11. #11
    Senior Member cam02ss's Avatar
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    For just a nasty street car get a wicked set of heads (Trickflows, ETs, AFRs,etc,) and pair it up to a healthy cam. I paired a set of stage 2+ heads up to a T Rex and got 463/402 on a mustang dyno through loudmouth exhaust. That was an M6 spinning 4.30s in a 12 bolt with 315 drags on the back. Keep in mind though that I upgraded my injectors and fuel pump and also had to have my pistons fly cut. I originally had 4.10 gears but had to bump to 4.30s to spin that cam down low. If you set your car up right you'll run low 11's all day long- I've got friends doing it.

    Once you start talking motor swap, etc. you better sit down and figure out a budget, because there is alot of stuff that comes into play that you don't think about. Alot of those are supporting mods. The car isn't going to be any fun if you spend that much money and keep breaking stuff, or can't put that power to the ground. Are you installing everything yourself? If not you'll have to calculate labor rates,etc.

    For a heavy nitrous shot you'll be safer using an iron block, stronger, etc. I went with an iron block 408 because I'm going to be spraying that thing into oblivion with a 300 shot. I ordered mine as a complete long block with stage 3 heads and sizeable cam. There are some good suppliers out there and I'll point you in the right directions if you want. Here's a list of mods that are currently on my car that I bought to "gear up" so to speak for the 408 or bought after the 408 was in. Granted, I switched from a 6 speed to a TH-400 because I'm going to be in the 9's on the bottle. Obviously you don't have to gear your car for the track.

    Engine Mods

    ARD built iron block 408
    -Callies Dragonslayer Crank
    -Callies Compstar rods
    -Clevite bearings
    -Diamond coated pistons (11.5:1 compression)
    -Texas Giant camshaft
    -LQ9 stage 3 heads 68CC combustion chambers, 340 CFM
    -Ported LS6 oil pump
    -Nick Williams 90mm TB
    -Victor Junior single plane intake w/ custom elbow

    Supporting Mods

    -LS1 motorsports air lid
    -Free mods
    -ATI TH400
    -ATI 3800 stall
    -Kooks 1 7/8 stepped headers into 3" collectors
    -custom true duals through single chamber flowmasters, side exit
    -Spohn subfram connectors
    -Spohn adjustable Torque arm
    -Spohn lower control arms
    -Spohn LCA relocation brackets
    -Spohn panhard bar
    -Spohn rear drag sway bar
    -Strange 12 bolt w/ 4.11's & full spool
    -QA1 front shocks
    -LCA
    Weight Reduction

    -Rear seat delets
    -AC removed
    -AIR system removed

    Nitrous

    -Zex plate system adjustable 200-300 shot.


    Wheels/Tires

    -15-3.5 Weld Prostars w/ skinnies
    -15x10 Weld Prostars w/ 325 Mickey Thompson ET Streets

    Tuning

    Tuning by Bret Shook at F Body Central. 476/443 on a mustang dyno spinning w/ 2 people sitting on the ass end of the car.


    I went to the track this past Wednesday and was snapping off low 11 sec passes all night with little effort. I'm wasn't launching the car correctly and was playing around with tire pressure throughout the runs. Once I get comfortable with the car and figure it out, it will run consistant 10's NA. All those runs were off the foot brake as well. My lowest pass was an 11.1 @ 124 w/ a 1.6 60' leaving between 3-3500 RPMs. Now I'm in the process of getting a 10 point cage.

    Basically it boils down to this- If you want a kick ass car that sounds mean as hell to drive on the street, do a mean H/C setup. Forget the juice and get a cam on a 110 LSA, have it hellishly tuned, get some badass heads and go have fun.

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    I have been building a 408 iron block, I bought the short block from Latemodelengines.com I thought originally that I would only spend about 7 grand. A few months later, I am at about 18 or so. I did have a lot bigger cam put in it than advertised and decided to go all out with the other parts, but i am hoping it will be well worth it.

    408 stroker
    Trick Flow 235 cnc ported with harland sharp rockers. - totalengineairflow.com
    kooks 1-7/8"-3" lt trp rumbler.
    fast 90 intake
    NW 90 TB
    Meizer water pump
    and quite a few other things.

    The cam lift is either .646 .646 or .646 .643, I can't remember.

    Wish me luck

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    Grand Imperial Wizard Sarge's Avatar
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    Retired Outlaw Sum Bitch

    Our sponsor Nelson Performance built me on bad ass 408.

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