Dart LS1 Pro Heads
06-30-2006, 06:47 PM
#1
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Dart LS1 Pro Heads I am building a 402 stroker, 4.00 stroke crank, 11:1 compression, 6.125 rods, 600+ lift cam, ls6 intake and bigger injectors. I have found a great deal on a set of Dart LS1 pro heads but dont know if they are too much for the engine that I am building. They come equipped with 225cc intake runners 2.05 intake valves and 1.60 exhaust with 62cc chambers. Are these heads to much for my set up?
06-30-2006, 08:16 PM
#2
Your 225 Dart choice sounds logical to me. Go for it!
But be sure to figure/set your compression ratio to 11.1 and set your Dynamic Compression Ratio (8.5:1-8.9:1 level) with correct cam timing.
Send PatrickG a PM, this is easy stuff to him he wll be glad to help you.
But be sure to figure/set your compression ratio to 11.1 and set your Dynamic Compression Ratio (8.5:1-8.9:1 level) with correct cam timing.
Send PatrickG a PM, this is easy stuff to him he wll be glad to help you.
Last edited by gollum; 07-01-2006 at 09:31 AM.
06-30-2006, 08:26 PM
#3
Here is a good article that will help you concerning DCR and correct valve events
You can order this custom grind from Thunder Racing but you may want to use a lower lift lobe because of your less than optimal flowing LS6 intake. If you purchase a Mamo ported 90mm FAST intake setup the higher LSK lobe will work.
Cam specs: 243/251, .600/.600 lift roughly, 110lsa (+2)
Originally Posted by Patrick G
Typically, you advance a cam that's too big and retard a cam that's too small. If you choose your cam carefully, you will not need much if any advance. 5 degrees of advance on your cam is going to severely exhaust-bias your cam and it will run out of breath too soon. Ideally, you want to choose your intake valve closing point to where it makes best power on a 408. From what I've seen, that means it should be around 48-50 degree ABDC IVC to work best with the FAST intake. Anything later than that will peak later than the FAST intake is trying to force.
The duration is going to be around 8 degrees bigger than what works with a 346. If a 234/242 G5X-3 works great in a 346, then a 242/250 would be close to equivalent in a 408. Too often though, I see mistakes being made by running too wide of an LSA in these larger motors. Truthfully, to get the DCR up into the 8.5-9.0 level, it's better to narrow the LSAs some and not advance the cams so much. This will center the overlap closer to TDC and will allow the motors to rev better past peak hp. An ideal street/strip 408 cam in my view would be something with LSK lobes like a 243/251 .653/.660 110LSA (+2). You get an IVC under 50 degrees ABDC and your overlap is exactly centered over TDC.
The duration is going to be around 8 degrees bigger than what works with a 346. If a 234/242 G5X-3 works great in a 346, then a 242/250 would be close to equivalent in a 408. Too often though, I see mistakes being made by running too wide of an LSA in these larger motors. Truthfully, to get the DCR up into the 8.5-9.0 level, it's better to narrow the LSAs some and not advance the cams so much. This will center the overlap closer to TDC and will allow the motors to rev better past peak hp. An ideal street/strip 408 cam in my view would be something with LSK lobes like a 243/251 .653/.660 110LSA (+2). You get an IVC under 50 degrees ABDC and your overlap is exactly centered over TDC.
Cam specs: 243/251, .600/.600 lift roughly, 110lsa (+2)
Last edited by gollum; 06-30-2006 at 08:55 PM.
06-30-2006, 08:32 PM
#4
Also make sure your heads are manufactured after the stated date below. Just to be sure you have no install problems with your OEM rocker pedestals clearing Darts bosses.
Originally Posted by Dart331Stroker
We have made a change in this jsut recently, so item machined after 4-10-06 will have date codes stamped on them, and we moved the machining .100 towards the centerline of the valve cover boss, this should help out with Crane fitment. It will also allow Jesel, T&D, and Comp shaft systems to fit.
Thanks
John
Dart
Thanks
John
Dart
06-30-2006, 08:52 PM
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i was just talking to someone about these same heads. wanted to jump on here and see if i can find anything. man what luck there is a new thread going about these heads right now. im thinking about going with these same heads for my 403.
06-30-2006, 09:07 PM
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I really like my dart heads, i gained 95 hp and 53 tq. with those heads and the cam in my sig. They arn't going to be as nice as say the afr/ETP heads, but for 1000 dollars less you can't beat them.
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06-30-2006, 09:18 PM
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Originally Posted by ThirdGenLS1
I really like my dart heads, i gained 95 hp and 53 tq. with those heads and the cam in my sig. They arn't going to be as nice as say the afr/ETP heads, but for 1000 dollars less you can't beat them.
$1000 less allows me to make my set up more complete with the fast 90/90. i was looking at ETP but could only afford to port the LS6 intake and re use it. i know that would hurt the max potential that the motor has.
i know these havent been out long. i hope more guys that have them chime in on their gains 346, 383, 402 or 408
