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Ls2 408 stroker

 
Old 06-03-2019, 08:53 AM
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Default Ls2 408 stroker



Gentleman, I thought to update you all on my progress with my engine build,
I heard back today from my engine builder and it's finally being put back together.
That 242/257 .660 .655 113 LSA +3 was installed and degreed, The specs were spot on and was installed two degrees advanced ( plus one degree of ground in advance)
The heads, rockers, valve springs, head valves etc have all been done.
I had to get slightly longer pushrods and unfortunately the 3/8 size pushrods could not fit without fouling the head so I had to go for 5/16 with a thicker 80 thou wall thickness.
These will be more than strong enough for my combination and high rpm power I am told.
The Isky high rpm lifters fitted without any clearance issues.

Engine is a LS2 408 stroker with the following combination:
CNC LS3 heads with 12:8.1 compression (runs on e85)
FAST 102mm intake manifold
3200rpm stall converter
3:91 rear gears
PAC 1209X valve spring kit
Yella Terra 1:8.1 ratio with 10mm bolt upgrade
Isky HPX high rpm hydraulic roller lifters
Cometic MLS head gaskets
Mezeire Electric water pump

Check out the pics below:

I do have one question for you guys though.
I am a little concerned about my stall converter and how it will behave once everything is back together.
The current stall converter was made for the previous 236/244 114 LSA camshaft which had 12 degrees of overlap and the new cam will have 23 degrees of overlap.
I feel that the stall converter may end up flashing higher and not drive as good because of the extra torque and power which will make the stall lose it's low end manners.
Do you guys think the stall converter will need to get taken out and readjusted to suit new cam or will it be ok?

Cheers
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Old 06-03-2019, 10:18 AM
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Call the Stall conv. Company n ask em what they think. Meanwhile, you already own it, so run it n see what you think bout it. Nice clean lookn build tho. I didnt know you could do 408 on an ls2. Is it sleeved? Im assuming not or you would have went more. Just curious why i usually see 402ci strokers for ls2...
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Old 06-03-2019, 10:32 AM
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408ci is just a 402ci opened up 0.030... which should be fine on stock LS2 sleeves, especially naturally aspirated.

That new cam should be nice. It will really let the engine sing. I can see your concern for the torque converter, but I would run it since you already have it.
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Old 06-03-2019, 10:46 AM
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Originally Posted by rkupon1 View Post
Call the Stall conv. Company n ask em what they think. Meanwhile, you already own it, so run it n see what you think bout it. Nice clean lookn build tho. I didnt know you could do 408 on an ls2. Is it sleeved? Im assuming not or you would have went more. Just curious why i usually see 402ci strokers for ls2...
My engine builder is going to drive the car and see how it drives and where it flashes.
If there is too much of a difference the stall converter will be taken out, sent away and modified, sent back and to get refitted.
I hope this doesn't happen as it's just another expense I would prefer to avoid but I knew the risks before I did this.
Which is why I was asking if anyone here has had any experience with this or not.

And yes, the build is nice and clean. The man is a perfectionist.

Most people do a 402 so they ran rebuild that block again in the future.
Once you go a 408 the block is a throw away if engine needs to get rebuilt again. There is not enough meat left in the bore to machine.
Same in an LS3. if you stroke it to a 427 the block is a throw away if it ever needs to get rebuilt which is why many go with a 416.
I already knew this, but I wanted it maxed out as this engine will remain NA and I certainly won't have anything breaking.
I will also be using either an LS9 or Dart Aluminium block for my next build depending if I go boosted or not so it's all good.
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Old 06-03-2019, 10:48 AM
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Good looking build. Who did the CNC on your heads?
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Old 06-03-2019, 10:55 AM
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Originally Posted by DavidBoren View Post
408ci is just a 402ci opened up 0.030... which should be fine on stock LS2 sleeves, especially naturally aspirated.

That new cam should be nice. It will really let the engine sing. I can see your concern for the torque converter, but I would run it since you already have it.
The cam was specified by bullet cams specifically to work with my heads and high compression ratio.With an IVC of 51 and EVO of 65 vs IVC 50 EVO 58 (old cam) there will be a substantial difference in the top end.
Engine will be able to run more rpm and make more power hopefully to 7000rpm this time.
My previous camshaft was too mild and just didn't pull that well past 6000rpm although it was good up to 5800rpm and below. Was nice and strong.
Bullet cams says that even with this larger stick the engine will make more torque from 2200rpm+ compared to my previous camshaft which I'm hoping is the case.

And yes engine will be perfectly fine.
It will only remain NA so it remains reliable. Having 650-700hp I think is enough for the street.
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Old 06-03-2019, 10:59 AM
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Originally Posted by Tuskyz28 View Post
Good looking build. Who did the CNC on your heads?
The CNC work on the heads was done by a hand porter years ago using his own designs. They flow really well which is why I made good power (505rwhp) with only a mild camshaft.
The machine shop chemically cleaned the heads this round when they went in to get the threads enlarged for the 10mm rocker bolts plus the new stainless valves and the seats etc.
Do they heads look CNC'ed in the picture?
I have never been able to compare a stock LS3 head VS a set of ported ones.
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Old 06-03-2019, 11:18 AM
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What do you guys think of the ports?

Note larger threads

Nice valve job?

Nice valve job? Close up
Here are some more close up pics of the heads after the machine shop:
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Old 06-03-2019, 11:26 AM
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Ummm... 113+3 means it has three degrees advance ground in. Are you saying to advanced it even more furtherer or did you install it dot to sit and it is on a 110 ICL?
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Old 06-03-2019, 11:36 AM
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Originally Posted by Darth_V8r View Post
Ummm... 113+3 means it has three degrees advance ground in. Are you saying to advanced it even more furtherer or did you install it dot to sit and it is on a 110 ICL?
Hi Darth.
There was one degree of advance built into the camshaft so it was on a 112 ICL.
The cam specs from the grinder was 242/ 257 .624 .622 113 +1.(the lift was for the standard rocker ratio) My installer likes to have room to move and he prefers to advance it himself too. Don't know why. Maybe it performs better. I don't know.... Maybe you can tell me.
The installer advanced it 2 more degrees and is on a 110 ICL.
So 3 degrees in total where it should be.
I hope I'm making sense.
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Old 06-03-2019, 11:41 AM
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Yup makes sense now
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Old 06-03-2019, 12:01 PM
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Originally Posted by Darth_V8r View Post
Yup makes sense now
How does everything look to you for this build?
What do you think of the head work?
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Old 06-03-2019, 12:14 PM
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Head work looks great from the pics. You may want a higher stall for that cam.
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Old 06-03-2019, 12:20 PM
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Originally Posted by Darth_V8r View Post
Head work looks great from the pics. You may want a higher stall for that cam.
Good to hear.
Bullet cams say I won't need higher stall speed due to this camshaft making more torque from 2200rpm+ compared to my previous camshaft.
Then again the original spec from Bullet was 242/254 114 LSA +4 with 20 degrees of overlap.
I had to modify it a little to get the same IVC and EVO as this camshaft which I achieved. Camshaft grinder could not grind those exact specs.
The only difference is my cam has 3 degrees extra overlap.
and the IVO and EVC was 11,9 for the bullet spec vs 11 13 for my cam.
Not sure if that small change will make any difference to the 2200rpm+ stronger torque curve to what bullet originally said.

What do you think?
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Old 06-03-2019, 12:54 PM
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Old 06-03-2019, 01:09 PM
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I'd get a tc that will flash to at least 3600. You will hit off the line with more torque and will launch harder. 4000+ stall may become a bit obnoxious to drive but people do it. Remember more slip means more heat so keep the trans fluid cool.
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Old 06-03-2019, 01:14 PM
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Originally Posted by rkupon1 View Post
Looks like it drives ok on the street.
However my 3200r drives almost like stock in the low end.
Pulls off idle and there is decent torque from 1800rpm+
I don't want to have to rev any higher to get the same effect
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Old 06-03-2019, 05:23 PM
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My converter flashes to 5000 and drives tight
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Old 06-03-2019, 06:07 PM
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Can’t really see much of the ports or valvejob, but it doesn’t look all that great. They didn’t blend in the top cut or do any work to the chamber at all.
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Old 06-03-2019, 06:39 PM
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Horsepower goals ?
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