Best DD Engine Build??

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,686
1,957
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Mid Michigan
Would you use a type of header or just stock manifolds?

I guess that money could then be used on a set of Mahle pistons.
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,736
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Texas!!!
I have stock passenger side, LML driver side, and ProFab 2" up pipes on my motor.
 

Ne-max

I like turtles
Nov 15, 2011
3,361
64
48
Lincoln, Ne
i like this Tom except for 800hp id pass on the uppipes/manifolds and use something other than stock pistons.

X2. People making double the hp with damn near the same size as stock. Only benefit of up pipes is the stronger bellows. Witch correct drive pressure should keep that in check
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,752
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Phoenix Az
bigger manifolds/up pipes really come into play when you are running a restricted turbo size but driving the heck out of it for max power. obviously the turbo hot side would have to outflow the stock up pipes (something in the 472 range and up or certain sled pull setups), then you gain the benefits of the higher flow and lower drive pressure from them. a stroker motor would see a benefit from them as well

Twins or large turbos not being pushed to extremes usually keep drive pressure in check due to staying in their map.
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,732
300
83
Boise, ID, USA
I built mine with 900+ HP in mind, but at relatively low torque, so probably more in line with a normal 700-800 HP build.

  • Stock block, .020" over (300k miles, it was at service limits)
  • Stock 300k mile LB7 crank (it magnafluxed as good), keyed
  • Carillo rods
  • Mahle race cast pistons with valve reliefs, 16.5:1 (probably should have stayed stock CR)
  • Stock flexplate (looked good, and relatively easy to replace when needed)
  • SoCal / ATI damper
  • Fully (externally) balanced,align hone on the crank journal, all new bearings
  • Stock 300k mile oil pump
  • Comp Cams most absurd cam (this might have been a mistake, but it sings at 5000 RPM!), normal fire order (I don't buy the AF saving the crank argument personally)
  • Wagler LB7 head (cast-in injector cups)
  • SoCal valve springs (any should work, I had these laying around)
  • +75% SAC injectors (probably will have to go up to 150% or more when I get air)
  • Single S371 turbo (all I could afford at the time)
  • LML driver side manifold, stock passenger manifold, RDL up-pipes
  • ARP fasteners everywhere
That setup makes 660 RWHP / 970 lb-ft. The low torque is by design, and was setup for my future plans.

The goal down the road is compound turbos, probably a 71 mm and a 90+ mm, so I can push 5000 RPM instead of choking out at 3600 RPM. If I can hold the same ~970 ft-lb up the rev range with the bigger turbo setup, that'll be a bit over 900 HP, which was my original goal.
 

gmduramax

Shits broke
Jun 12, 2008
4,082
252
83
Nor cal
I have stock passenger side, LML driver side, and ProFab 2" up pipes on my motor.

Doesn’t the lml manifold flow more than 01-10 manifolds? I thought I remember seeing where people would port the 01-10 manifold before it goes into the up pipe and the lml manifold you didn’t need to.
 

ikeG

Oughta Know Better
Apr 19, 2011
2,472
152
63
Western PA
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Any amount you over bore will help with airflow, unshrouding the valves. It would be minuscule, and extremely expensive/hard to measure gains but its a major reason I wouldn't be afraid to over bore when replacing pistons. Do not waste money on exhaust parts before budgeting for motorsports pistons either.

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20dmax08

Member
Apr 13, 2018
57
0
6
Wouldn’t the benefit of lower egts with manifolds and up pipes be worth it?


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Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
Wouldn’t the benefit of lower egts with manifolds and up pipes be worth it?


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But do they? That claim could vary by a large margin as there is so many different ways to make power
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,736
806
113
Texas!!!
More fuel and more power means higher EGTs. There is no way around that.
 

Nickracer9

Member
May 23, 2012
203
1
18
Put your money on the best internals you can afford(rods+pistons+studs) otherwise it will always be in the back of your mind every time you use your truck on a long haul. FYI I didn’t gain anything from manifolds and up pipes on the dyno in the 600whp range.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,686
1,957
113
Mid Michigan
I found it interesting the reasons given for mani's and up's. Considering how hard I pushed my stock turbo, it makes sense they helped me.
 

20dmax08

Member
Apr 13, 2018
57
0
6
Interesting! This good thread and full of knowledge! Learning quite a lot!


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Blackmax123

Member
Aug 2, 2014
683
1
18
central Pennsylvania
Incorrect. The 01-10 were choked down to fit an application that GM never ended up using. The lml is the first year to have the manifolds not choked down like the 01-10

Sorry ment to type isn't choked down.. lol

My last lml build consists of.

Stock block, 40 over, mahle race casts, with valve reliefs
Billet mains, callies compstar crank, wagler rods, studded mains, head, and rocker bridges, dorman oil cooler, DP water pump, wagler stg 1 af cam, wagler valve springs, had the heads gone through. 10mm stroker cp3 swap. I did get a set of prefab manifolds and uppipes because I traded my stock lml stuff for them.. maybe a little over built for my needs but hoping to not have to ever do it again.