Help Me Spec New Darton 427
11-28-2018, 08:39 AM
#21
10 Second Club
I’d use a sleeved ls2 block instead of 5.3 as the windage inside a 5.3 block can eat some HP
the PRC heads that you’re looking at or FED ported ls3’s. They have some wicked high flowing ported stock ls3 programs. 380+ CFM
johnson short travel hydraulic lifters, Cam to spin to 7600+
low rise holley sniper intake
this will get you around your goal
the PRC heads that you’re looking at or FED ported ls3’s. They have some wicked high flowing ported stock ls3 programs. 380+ CFM
johnson short travel hydraulic lifters, Cam to spin to 7600+
low rise holley sniper intake
this will get you around your goal
11-28-2018, 09:25 AM
#22
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I would humbly suggest another option, LSX Iron block the 110 lbs will only matter for
dedicated HPDE & Autocross, but you get a MUCH better priority Main Oil system
and a stronger foundation for anything down the road.
4.155 Bore X 4.00 Stroke for 434".
I Absolutely Love Darth's 238/246 115+2 Cam Specs!
Especially in combination with AFR LS3 Heads, have
Tony put light weight valves and the appropriate springs for your
cam lift & RPM.
Out of the box these heads flow enough Intake for 750+ Flywheel HP
from a 260 CC, more than the PRC 285 LS7, and far better on the exhaust
which won't require the 12+* Exhaust split making it much better for a daily driver.
The AFR deck is much thicker & stronger than ported OE castings, and I
think have a 6 bolt option as well, to go with the LSX Block if you like.
The Fast Intake fits the F Body & C5 for that matter much better than the MSD
(which Absolutely requires porting due to poor QC from the maker).
With both standard length & mid length runners you have
"The Best of Both Worlds" from an intake standpoint, standard runners for
Street & daily driver duties which will peak 6200-6500 ~550+ RWHP, rolling over ~6800,
but stop and go driving will be a piece of cake with Darth"s Cam specs.
30-45 minutes to switch out the runners will peak
6800-7000 ~575+ carrying to 7500 and .3-.5 quicker in the 1/4
(maybe 600+ with vacuum pump,ewp, and all the fixings.
I would target 11.5-12.0:1 Compression with 93, your tune will be critical.
I would prioritize additional work by Tony on the heads VS porting on the
Fast especially vs the Mid length runners, The Best Heads will allow you to
reach your goals with a smaller cam and be much more fun to drive as a
"Daily Driver", but again I don't think needed for your goals.
Engine should easily last 75K+ miles with Quality oil ( I use Amsoil) and
Making sure oil and water is up to temp before WOT (160*/180* minimum)
Valve springs will need to be checked periodically ~3-5K, and replaced @
~15-25K again depending on lift and usage ie # of track days.
TSP, just to name one has 427-454" LSX Short Blocks for ~$7500
sleeved OE short blocks ~$6500.
It would be cheaper to go turbo......some guys just crave NA.
Just my .02
dedicated HPDE & Autocross, but you get a MUCH better priority Main Oil system
and a stronger foundation for anything down the road.
4.155 Bore X 4.00 Stroke for 434".
I Absolutely Love Darth's 238/246 115+2 Cam Specs!
Especially in combination with AFR LS3 Heads, have
Tony put light weight valves and the appropriate springs for your
cam lift & RPM.
Out of the box these heads flow enough Intake for 750+ Flywheel HP
from a 260 CC, more than the PRC 285 LS7, and far better on the exhaust
which won't require the 12+* Exhaust split making it much better for a daily driver.
The AFR deck is much thicker & stronger than ported OE castings, and I
think have a 6 bolt option as well, to go with the LSX Block if you like.
The Fast Intake fits the F Body & C5 for that matter much better than the MSD
(which Absolutely requires porting due to poor QC from the maker).
With both standard length & mid length runners you have
"The Best of Both Worlds" from an intake standpoint, standard runners for
Street & daily driver duties which will peak 6200-6500 ~550+ RWHP, rolling over ~6800,
but stop and go driving will be a piece of cake with Darth"s Cam specs.
30-45 minutes to switch out the runners will peak
6800-7000 ~575+ carrying to 7500 and .3-.5 quicker in the 1/4
(maybe 600+ with vacuum pump,ewp, and all the fixings.
I would target 11.5-12.0:1 Compression with 93, your tune will be critical.
I would prioritize additional work by Tony on the heads VS porting on the
Fast especially vs the Mid length runners, The Best Heads will allow you to
reach your goals with a smaller cam and be much more fun to drive as a
"Daily Driver", but again I don't think needed for your goals.
Engine should easily last 75K+ miles with Quality oil ( I use Amsoil) and
Making sure oil and water is up to temp before WOT (160*/180* minimum)
Valve springs will need to be checked periodically ~3-5K, and replaced @
~15-25K again depending on lift and usage ie # of track days.
TSP, just to name one has 427-454" LSX Short Blocks for ~$7500
sleeved OE short blocks ~$6500.
It would be cheaper to go turbo......some guys just crave NA.
Just my .02
Last edited by NAVYBLUE210; 11-28-2018 at 01:53 PM.
11-28-2018, 10:40 AM
#23
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regarding windage, you could always run a VP and pretty much negate the windage issue.
MAVN, I agree. You don't need the huge budget to hit the power goals, if power is your only goal. Same kind of thing as Tusky posted. you can always cam it bigger to make the power and get by with less cylinder head.
MAVN, I agree. You don't need the huge budget to hit the power goals, if power is your only goal. Same kind of thing as Tusky posted. you can always cam it bigger to make the power and get by with less cylinder head.
11-28-2018, 12:26 PM
#25
KCS – Thanks for sharing that post. Obviously more than I need but definitely a cool read. Any other useful info you have will always be appreciated.
So far, I’ve contacted RED who referred me to LME and HPR. Exchanged some emails with Anthony at HPR and waiting a response with different packages they offer. They use a shorter piston and rings to limit piston rock which they also use in an LS3 to get even more cubes out of it. Looking forward to his quotes since the 454 they have on their website looks very promising. I did explain to him that oil consumption and longevity are very important to me.
So far, I’ve contacted RED who referred me to LME and HPR. Exchanged some emails with Anthony at HPR and waiting a response with different packages they offer. They use a shorter piston and rings to limit piston rock which they also use in an LS3 to get even more cubes out of it. Looking forward to his quotes since the 454 they have on their website looks very promising. I did explain to him that oil consumption and longevity are very important to me.
I’m using a piston design in my 440ci LS which is pretty similar to what HPR uses. So far, I have haven’t any issues with it and I have them in a block with relatively short cylinders. A sleeved block with the longer cylinders would be pretty happy with those pistons.
11-28-2018, 11:07 PM
#26
Mavn…you’ve got me thinking/researching. Impressed about the 50k miles on a stroked, standard sleeve LS3 and MPG…especially with that huge cam
Big Hammer- I research FED earlier this year…they seem ‘similar’ to mamo. I may need to get comfortable with longblock assembly if I go with either of them as its becoming apparent that at my power level, streetability and longevity, the right heads are going to be crucial
Navyblue – I can’t get used to the idea of iron under the hood. I love carving corners and even if it the weight wasn’t making a difference, I’d think it was. I’m glad I’m in the ballpark with CR. I’m considering shortblock and heads from separate vendors and self-assembly.
Darth – Good point, running a vacuum pump and go with the stronger 5.3 block may be worth it especially since upgrading to a LS2 may cost about the same. Thing about huge cam is streetability and longevity, which are also my main goals.
Jake – Thanks for the support. I often think about boosting too…but trying to keep it simple.
KCS – HPR explained those type of pistons to me, they just sound scary for some reason. Anthony at HPR really has me thinking about them…waiting to hear back from him.
I emailed Tony today to see what he has time for between now and march.
I’ll reach out to HPR again tomorrow and will call LME tomorrow as well.
Seems like California and Texas are battling each other to become the LS capital of the world!
Big Hammer- I research FED earlier this year…they seem ‘similar’ to mamo. I may need to get comfortable with longblock assembly if I go with either of them as its becoming apparent that at my power level, streetability and longevity, the right heads are going to be crucial
Navyblue – I can’t get used to the idea of iron under the hood. I love carving corners and even if it the weight wasn’t making a difference, I’d think it was. I’m glad I’m in the ballpark with CR. I’m considering shortblock and heads from separate vendors and self-assembly.
Darth – Good point, running a vacuum pump and go with the stronger 5.3 block may be worth it especially since upgrading to a LS2 may cost about the same. Thing about huge cam is streetability and longevity, which are also my main goals.
Jake – Thanks for the support. I often think about boosting too…but trying to keep it simple.
KCS – HPR explained those type of pistons to me, they just sound scary for some reason. Anthony at HPR really has me thinking about them…waiting to hear back from him.
I emailed Tony today to see what he has time for between now and march.
I’ll reach out to HPR again tomorrow and will call LME tomorrow as well.
Seems like California and Texas are battling each other to become the LS capital of the world!
11-29-2018, 12:07 AM
#27
10 Second Club
The thing is making Big hp and making big hp on a streetable engine are two different things.
theres a guy who made 800 hp with a stock CI LS3 and ported Stock ls3 castings. Naturally aspirated. Peaked over 8000
rpm.
I was going to use ported Stock castings on my car but there’s just more work arounds. Hard to get the compression up without milling and they’re already a PTV limited head. But the reason right ported ls3 heads can make nutty HP
theres a guy who made 800 hp with a stock CI LS3 and ported Stock ls3 castings. Naturally aspirated. Peaked over 8000
rpm.
I was going to use ported Stock castings on my car but there’s just more work arounds. Hard to get the compression up without milling and they’re already a PTV limited head. But the reason right ported ls3 heads can make nutty HP
11-29-2018, 06:38 AM
#28
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The thing is making Big hp and making big hp on a streetable engine are two different things.
theres a guy who made 800 hp with a stock CI LS3 and ported Stock ls3 castings. Naturally aspirated. Peaked over 8000
rpm.
I was going to use ported Stock castings on my car but there’s just more work arounds. Hard to get the compression up without milling and they’re already a PTV limited head. But the reason right ported ls3 heads can make nutty HP
theres a guy who made 800 hp with a stock CI LS3 and ported Stock ls3 castings. Naturally aspirated. Peaked over 8000
rpm.
I was going to use ported Stock castings on my car but there’s just more work arounds. Hard to get the compression up without milling and they’re already a PTV limited head. But the reason right ported ls3 heads can make nutty HP
Pbarby, It boils down to what you call streetable. Big cubes and outstanding heads are going to help you make your ride more drivable. The better (more efficient) head you employ here, the smaller the cam required, and that’s where the streetability standard comes into play. I prolly sound like Tony Mamo’s fanboi, but do your research. His LS7 program is unbeatable for a street head. Period. If you want a race head, there’s plenty others. If you want streetability with a max effort N/A build, he’s your guy. Small intake port means high velocity charge. That’s the key to making the power across the board with a street build. You can make the same power with a GM casting, and save money, but it won’t be as streetable.
11-29-2018, 11:00 AM
#29
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Darth – Good point, running a vacuum pump and go with the stronger 5.3 block may be worth it especially since upgrading to a LS2 may cost about the same. Thing about huge cam is streetability and longevity, which are also my main goals.
...
The thing is making Big hp and making big hp on a streetable engine are two different things.
Darth – Good point, running a vacuum pump and go with the stronger 5.3 block may be worth it especially since upgrading to a LS2 may cost about the same. Thing about huge cam is streetability and longevity, which are also my main goals.
...
The thing is making Big hp and making big hp on a streetable engine are two different things.