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LS7 combination opinions wanted

 
Old 05-09-2019, 08:00 PM
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Default LS7 combination opinions wanted

This posting is for my friend down here in Australia who has one of the special edition VE HSV's which came with the LS7 engine.
The engine is apart at the moment for some much needed work to get this thing really moving.
The purpose of this build is to be a weekend warrior and not a daily and therefore the engine will be quite aggressive.
This is the combination:
CNC LS7 heads with 62CC chambers Compression is around 13:1.1
MSD intake
3:73 gears
stall converter will be ordered after cam selection is made.
248/262 .680 .665 112 LSA +3

Combo looks good to me but my knowledge is limited.

What do you guys reckon?


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Old 05-09-2019, 08:23 PM
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ASSuming he’s staying with a hydraulic roller? Cam specs look good to me. That’s a lot of compression, which I am a fan of. I’m running 12.42 in my 434. What fuels are available to you guys down there? He left bottom end alone?
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Old 05-09-2019, 08:41 PM
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Originally Posted by Che70velle View Post
ASSuming heís staying with a hydraulic roller? Cam specs look good to me. Thatís a lot of compression, which I am a fan of. Iím running 12.42 in my 434. What fuels are available to you guys down there? He left bottom end alone?
He is running pump e85 like me.
Good thing about the e85 here is that it's consistent all year round with an 85-90% ethanol content.
We have the same fuel as the USA although the octane ratings are different. For example your 93 octane is the same our 98 octane fuel. Different measurements.
And yes it's a hydraulic roller.
Bottom end is stock.
His hoping there will be enough PTV clearance. If not new pistons will need to be fitted.
I like the camshaft selection too.
Looks like the IVC of 53 and EVO of 66 suit the compression he has.
He was telling me something with high compression you need to open your exhaust earlier and extend the IVC a bit later
Should make some crazy power.
I knew of this guy down here who had 17.1 compression NA.
on a 402 he had to extend his IVC to 56 and his EVO to 69 if i remember correctly because of the compression.
Apparently if you don't it can make the engine not perform as well
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Old 05-10-2019, 07:29 AM
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What rocker setup is he planning to use with such a big lift hydraulic cam ?
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Old 05-10-2019, 08:20 AM
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Originally Posted by fnbadaz06 View Post
What rocker setup is he planning to use with such a big lift hydraulic cam ?
I'd bet a dollar he'll be using Yella Terras.....

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Old 05-10-2019, 10:32 AM
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Originally Posted by fnbadaz06 View Post
What rocker setup is he planning to use with such a big lift hydraulic cam ?
Yella Terra platinum rockers.
These are rated to 900LB open spring pressure which is more than enough for his application.
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Old 05-10-2019, 10:33 AM
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Originally Posted by KW Baraka View Post
I'd bet a dollar he'll be using Yella Terras.....

KW
You won the bet.
I hope you have changed those mid length runners back to the long version by now!
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Old 05-13-2019, 11:00 AM
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62cc head is more like 12:1 compression. How is he calculating 13:1? Camshaft looks good. Not a fan of YT rockers or the MSD intake.
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Old 05-13-2019, 11:14 AM
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With a 4.125 bore and flat top pistons it was my understanding that 64-65 cc equaled 12:1 compression. That's what was on my 427.
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Old 05-13-2019, 11:28 AM
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66cc chambers on my WCCH Stage 2 OEM heads (.030 mill), with standard OEM head gaskets, came in at 11.7 static compression.
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Old 05-13-2019, 11:34 AM
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Originally Posted by jayyyw View Post
62cc head is more like 12:1 compression. How is he calculating 13:1? Camshaft looks good. Not a fan of YT rockers or the MSD intake.
Why don't you like the yella terras and the msd?
What would you recommend instead?
62cc would be close to 13 on a 427.
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Old 05-13-2019, 11:40 AM
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Originally Posted by Bill00Formula View Post
With a 4.125 bore and flat top pistons it was my understanding that 64-65 cc equaled 12:1 compression. That's what was on my 427.
So 62 cc chambers would equal?
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Old 05-13-2019, 11:58 AM
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I sure wish we had e85 here in nj...i prolly would have pushed the envelope with a solid roller and drysump set up. Along with e85, man thatd make sum power
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Old 05-13-2019, 06:50 PM
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Originally Posted by bortous View Post
So 62 cc chambers would equal?
Assuming a flat top piston, a zero deck and a 0.050 compressed thickness gasket I get 13:1
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Old 05-14-2019, 12:45 PM
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Originally Posted by 01CamaroSSTx View Post
Assuming a flat top piston, a zero deck and a 0.050 compressed thickness gasket I get 13:1
https://www.summitracing.com/newsand...ion-calculator

4.125" bore
4.000" stroke
62cc Head Volume
5cc Piston Volume (standard flat top with valve reliefs)
.000" Deck Clearance
.051" Head Gasket
8 cylinders

12.2:1 Static Compression
427.65 Cubic Inch

What this calculator does not take into account is:

1) "crevice volume" (distance from piston top to the top ring
2) Head Gasket Bore


You can also try this one. I get the same result.

http://www.csgnetwork.com/compcalc.html
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Old 05-14-2019, 03:09 PM
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Originally Posted by bortous View Post
Why don't you like the yella terras and the msd?
What would you recommend instead?
62cc would be close to 13 on a 427.
Not on a SBE LS7. 12:1-12.3

I would use the T&D adjustable rocker that mounts on the stock pedestal.

MSD is the better of the plastic intake manifold offerings. If you have clearance concerns, I'd run the MSD. What are your goals for the setup?

I made 646whp on a SBE LS7, LME ported stock heads, milled to 63.5cc, cometic .041" headgaskets, a Holley Hi Ram, 243/258 .660/.660 114+3 cam, 1-7/8" headers, and e85. That setup trapped 142.5mph in 2000DA.
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Old 05-14-2019, 03:59 PM
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Nothing wrong with the YT rockers when setup properly.
Lots of guys making 650-680 with Mamo MSD.
Hi Jay.
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Old 05-14-2019, 07:22 PM
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I just rechecked and get 12.2:1 also. I didn't take into account for the 5cc valve reliefs.
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Old 05-15-2019, 10:28 AM
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Originally Posted by Che70velle View Post
Nothing wrong with the YT rockers when setup properly.
Lots of guys making 650-680 with Mamo MSD.
Hi Jay.
Hi there
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Old 05-15-2019, 10:56 AM
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Originally Posted by Che70velle View Post
Nothing wrong with the YT rockers when setup properly.
Lots of guys making 650-680 with Mamo MSD.
Hi Jay.
Do you know if mamo uses the ultra lite pro's or the pro street in his builds?
Looks to me they are the ultra lite pros.
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