A dependable street/strip 6.7 Build.

SPEEDSHIFT

SPEEDSHIFT

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Jan 30, 2007
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Im going to build a 6.7 for my 04 soon, and wanted to get some honest opinions on the build. This truck is my DD and I do tow my crawlers with it now, so I really just want an all around good engine that makes highish HP, probably something around 850 on fuel. I want a quicker spooling, low smoke, effitient engine, something I think everybody would appreciate in a DD.

What ive got:

Complete lower mileage 6.7 pullout with 1 bad injector possibly.
ED 66/73/14 T3 (plan running twins later to get to 850hp)
06 Head w/ milled intake, bowl work, P&P, 110 spings.
24v polished/ cryoed rods.


Planning to use:

66/??? twins
header
dual stock pumps
120-180hp nozzles
MLS w/625s
Rod and Main studs


On the fence about:

Performance Cam
Primary turbo size
06 head or 6.7 head
Nozzles
Pistons


Discuss- For the guys running EFI Live on a 6.7, would you recommend a cam swap? Do you think its worth the $$ and hassle of using one over the stocker? Anybody got a back to back dyno on a similar setup for effitiency, hp, tq, egts, boost, anything showing a cam helps a 6.7CR with EFI making a significant difference?

06 Head on a 6.7, since I already have a bunch of work sunk into the 06 head, would there be any reason to use the 6.7 head? I know it has the matching coolant ports, but is that a big deal?

Pistons, is there a marine 6.7 piston?

I thought about dong a destroked 6.7, but $4k rods are not in the cards, and I think it will hold up just fine at 850hp and the way I drive.

Appreciate the info!:Cheer:
 
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Your going to want billet rods either way if your running twins on a 6.7. I've seen plenty of people learn that lesson the hard way.
 
I doubt you'll get to 850 with those nozzles too. I would say you'd probably need 250hp or more. Just my opinion from my experience with a 6.7 and a 66mm.
 
longhorn859 said:
Your going to want billet rods either way if your running twins on a 6.7. I've seen plenty of people learn that lesson the hard way.
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I plan on tuning it down a bit on the bottom end, I think it will be ok. Id also rather bend a rod than break a crank.

I may end up running a large single, just gotta get a feel for it.
 
SPEEDSHIFT said:
I plan on tuning it down a bit on the bottom end, I think it will be ok. Id also rather bend a rod than break a crank.

I may end up running a large single, just gotta get a feel for it.
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If your gonna tone it down on the bottom end, just stay with a 5.9. Cheaper etc.
 
How about decompressing it a little, to help live? Maybe just de-lip the stock pistons?
 
SPEEDSHIFT said:
How about decompressing it a little, to help live? Maybe just de-lip the stock pistons?
Click to expand...


Again, to me one of the big advantages of the 6.7 is the bottom end torque. If your going to take the torque out of it, just go with a 5.9, put the money you saved into a better turbo?
 
I already have the 6.7 and the 5.9 has 45k miles on it, so its time for something new anyway. LOL

Ill just change the tune up for what im doing because I want all the low end for the street and the HP when I race. Ill just build a street tune and a race tune.
 
SPEEDSHIFT said:
I already have the 6.7 and the 5.9 has 45k miles on it, so its time for something new anyway. LOL

Ill just change the tune up for what im doing because I want all the low end for the street and the HP when I race. Ill just build a street tune and a race tune.
Click to expand...


Put some billet rods in it. They tend to break racing as well. LOL

I just think you could sell the 6.7, and use that money to get a better turbo that would give you good bottom end.
 
Bodie I know you don't wanna sink $2500 - 3000 into billet rods but it's mandatory if you want use the word reliable in your build. We pulled two engines this week that were under 900hp that had shot peened 12V rods and all of the rods we bent, some much worse then others, and if your going with twins on a 6.7 just do yourself a favor and put billet rods in it the first time.

Lavon
20121030_105632-1.jpg
 
A ED 66/74/.9 over ED 480/96/88/1.32 makes a wicked twin setup Btw.
 
If you go with a big single you will be fine. No need for twins on a 6.7 if your gonna stay under 1000 hp. It will spool about any s400 by itself if its tuned right.

Or, if you wanna get rid of the 6.7, ill trade you a 5.9 for it.
 
At the same power level the 6.7 feels stronger because of the faster spooling and better low end. Both people that work with me have driven it now with the 6.7 and agree its alot nicer to drive with the new motor. I wouldn't want a big single on mine, but with a common rail I guess you can tune around just about anything.
Big difference in towing too.
 
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Blacksdieselhp said:
If you go with a big single you will be fine. No need for twins on a 6.7 if your gonna stay under 1000 hp. It will spool about any s400 by itself if its tuned right.

Or, if you wanna get rid of the 6.7, ill trade you a 5.9 for it.
Click to expand...

Thanks but I have a couple 5.9s along with the one that's in it right now.

I'm kinda leaning towards a larger single now... If I go that route I'll probably have ED build me a nice billet wheel S400, maybe a 72mm or so... What would you recommend? I'm just fine with larger chargers, I've been driving this 66mm on the truck with stock injectors since I built it. I wanted twins, but maybe a large single is the way to go for me as it would save a lot of money.
 
SPEEDSHIFT said:
Thanks but I have a couple 5.9s along with the one that's in it right now.

I'm kinda leaning towards a larger single now... If I go that route I'll probably have ED build me a nice billet wheel S400, maybe a 72mm or so... What would you recommend? I'm just fine with larger chargers, I've been driving this 66mm on the truck with stock injectors since I built it. I wanted twins, but maybe a large single is the way to go for me as it would save a lot of money.
Click to expand...

If your going to do a single why not run a better charger like a GTX4294R or a GTX4202R. Those chargers spool like smaller chargers but flow a lot better up top. To me if you've got the coin it's a no brainer.

S471 flows 89 lbs/min. Gtx4294R flows 98 lbs/min
S476 flows 104 lbs/min. Gtx4202R flows 114 lbs/min

With better spool up...
 
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