402 engine build qustions
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Joined: Feb 2014
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402 engine build qustions
my motor craped out on me the other day so I will have to do a rebuild. really thinking about doing a ls2 402 short block, maybe a custom cam, and using my stock 243 heads and stock intake. would this be a good idea? let me know what you guys think I should do. thanks!
My car is a 2006 m6 with cai, cam, sprint booster. that's about it on performance.
My car is a 2006 m6 with cai, cam, sprint booster. that's about it on performance.
Last edited by k_stewart_21; May 6, 2015 at 06:45 PM.
Burning Brakes
Joined: Mar 2012
Posts: 836
Likes: 43
From: Killeen Texas
my motor craped out on me the other day so I will have to do a rebuild. really thinking about doing a ls2 402 short block, maybe a custom cam, and using my stock 243 heads and stock intake. would this be a good idea? let me know what you guys think I should do. thanks!
My car is a 2006 m6 with cai, cam, sprint booster. that's about it on performance.
My car is a 2006 m6 with cai, cam, sprint booster. that's about it on performance.
There are some good points to consider in this article. Number 8 explains about stroker builds to give you an idea what is and what is not a good idea. All the points are things to think about.
Last edited by dmoneychris; May 8, 2015 at 10:36 AM.
Burning Brakes
Joined: Mar 2012
Posts: 836
Likes: 43
From: Killeen Texas
His original comment was about building a 402 ci. Stroker engine not going the Forced Induction route. (He did ask if the "LS2 402 short block" would be a good idea, so I guess you're opinion is not to far off base, but you didn't address his original question of if it was a good idea. If the FI route is 'better' you should have some stuff to support your opinion. I'm sure he's thought about both routes before making the original post.
Last edited by dmoneychris; May 8, 2015 at 10:35 AM.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
Do a little research RE: the crank. The cost of balancing the stock crank to the increased weight of the forged rods and pistons is fairly hefty, enough to make the cost of the after market crank along with additional cubes, more appealing. You can get a 4" forged crank for <$800.
Also you'll want to take yours apart first. Depending on your definitiion of "crapped out" it may need to be sleeved. The LS2 sleeves can only really take a .005" bore/hone.
Also you'll want to take yours apart first. Depending on your definitiion of "crapped out" it may need to be sleeved. The LS2 sleeves can only really take a .005" bore/hone.
Pro
Joined: May 2009
Posts: 611
Likes: 3
From: Milwaukee WI
St. Jude Donor '13
If you are going to spend on a stroker build I wouldn't reuse the oem intake manifold. You could sell your ls2 intake for 3-400bux and get a fast or the new msd intake if it's available. The ls2 intake is the red headed stepchild of the ls family when it comes to flow and hp.
Le Mans Master
Joined: Dec 2005
Posts: 6,999
Likes: 1,684
From: Southeast TX
I agree with Winters97 (just for the record, it's this time and this time only
). To do any good with more cubes in an LS2, you need heads, more cam and valve train, Fast intake, etc. Vs rebuilding what you have with the stock crank and adding a basic centri blower kit. A few more bucks, but way better bang for those bucks. You more than likely don't need to replace the crank, don't need to do anything to the cam/valve train, don't need a different intake mani, etc. Plus, the ceiling is WAY higher and you keep stock like drivability and fuel eco.
). To do any good with more cubes in an LS2, you need heads, more cam and valve train, Fast intake, etc. Vs rebuilding what you have with the stock crank and adding a basic centri blower kit. A few more bucks, but way better bang for those bucks. You more than likely don't need to replace the crank, don't need to do anything to the cam/valve train, don't need a different intake mani, etc. Plus, the ceiling is WAY higher and you keep stock like drivability and fuel eco.
Le Mans Master
Joined: Dec 2007
Posts: 8,375
Likes: 97
From: Somewhere in the Mid 9's TX
I agree with Winters97 (just for the record, it's this time and this time only). To do any good with more cubes in an LS2, you need heads, more cam and valve train, Fast intake, etc. Vs rebuilding what you have with the stock crank and adding a basic centri blower kit. A few more bucks, but way better bang for those bucks. You more than likely don't need to replace the crank, don't need to do anything to the cam/valve train, don't need a different intake mani, etc. Plus, the ceiling is WAY higher and you keep stock like drivability and fuel eco.
). To do any good with more cubes in an LS2, you need heads, more cam and valve train, Fast intake, etc. Vs rebuilding what you have with the stock crank and adding a basic centri blower kit. A few more bucks, but way better bang for those bucks. You more than likely don't need to replace the crank, don't need to do anything to the cam/valve train, don't need a different intake mani, etc. Plus, the ceiling is WAY higher and you keep stock like drivability and fuel eco.
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Le Mans Master
Joined: Apr 2011
Posts: 7,820
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From: Montreal
St. Jude Donor '13
If you are going to spend on a stroker build I wouldn't reuse the oem intake manifold. You could sell your ls2 intake for 3-400bux and get a fast or the new msd intake if it's available. The ls2 intake is the red headed stepchild of the ls family when it comes to flow and hp.
Pro
Joined: May 2009
Posts: 611
Likes: 3
From: Milwaukee WI
St. Jude Donor '13
Flow isn't the greatest. Just like back in the day swapping out the weaker ls1 manifold to the ls6 gave a nice gain, swapping the ls2 for a ported fast102 produces a really nice gain(throughout the curve). Although more significant gains than the the ls1 to ls6 swap ever did(20-30rwhp). It's one of the best mods for the money on an ls2. The oem ls3 manifold is a much better flowing so most people usually just port their stocker. There are lots of threads here and on ls1tech with Dyno results of fast102 installs on an ls2.
If doing a N/A ls2 build whether bolton, h/c or stroker it's a worthwhile mod.
If doing a N/A ls2 build whether bolton, h/c or stroker it's a worthwhile mod.
Last edited by brewcitygymratt; May 11, 2015 at 02:06 PM.
Le Mans Master
Joined: Apr 2011
Posts: 7,820
Likes: 411
From: Montreal
St. Jude Donor '13
Just like back in the day swapping out the weaker ls1 manifold to the ls6 gave a nice gain, swapping the ls2 for a ported fast102 produces a nice gain. Although more significant the the ls1 to ls6 swap ever fid(20-30rwhp). It's one of the best mods for the money on an ls2. The oem ls3 manifold is a much better flowing so most people usually just port their stocker. There are lots of threads here and on ls1tech with Dyno results of fast102 installs on an ls2.
If doing a N/A ls2 build whether bolton, h/c or stroker it's a worthwhile mod.
If doing a N/A ls2 build whether bolton, h/c or stroker it's a worthwhile mod.
I guess on N/A it could make sense.
Pro
Joined: May 2009
Posts: 611
Likes: 3
From: Milwaukee WI
St. Jude Donor '13
Yeah if boosted it's a waste of money. Sometimes I wish I went the boost route instead of my h/c/fast build. The 580rwhp+ on meth thing is really enticing. I'm on the fence on adding boost due to having 89xxx miles on my ls2.
Intermediate
Joined: Aug 2013
Posts: 27
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Is 521/468 underwhelming? 402 with FAST 102, NW 102 TB and Advanced Inductions 243 heads. It is a very well planned out build though. Just finished it and very pleased.
Burning Brakes
Joined: Mar 2010
Posts: 767
Likes: 12
From: Keller TX
What are your cam specs and compression? My roadrace LS3 made 522/488 on a stock displacement LS3 with stage 1 ported LS3 heads, stock intake and stock TB, 93 octane pump gas. The 16lb clutch, 3" dual unrestricted exhaust and dry sump all help make more power than a street car can get to, but still.
Intermediate
Joined: Aug 2013
Posts: 27
Likes: 0
Nope not at all. And you invested in a FAST and expensive TB to get there, which was smart. For the price of that intake, TB and the porting on those heads, he could sell his top end, get a set of LS3 heads and intake/TB, and he wouldn't be too far behind and be money ahead. Just didn't want him to go down the path of 243 heads trying to breath through an LS2 intake and expecting to make your numbers.
What are your cam specs and compression? My roadrace LS3 made 522/488 on a stock displacement LS3 with stage 1 ported LS3 heads, stock intake and stock TB, 93 octane pump gas. The 16lb clutch, 3" dual unrestricted exhaust and dry sump all help make more power than a street car can get to, but still.
What are your cam specs and compression? My roadrace LS3 made 522/488 on a stock displacement LS3 with stage 1 ported LS3 heads, stock intake and stock TB, 93 octane pump gas. The 16lb clutch, 3" dual unrestricted exhaust and dry sump all help make more power than a street car can get to, but still.
My cam is 245/256 620/595 112+3 and my CR is 11.8.
I may have a few ponies left if I port match the intake but it is completely untouched, right out of the box.