DD2K throwing me off, iron Vortecs better than Fastburns?
10-06-2008, 09:46 AM
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DD2K throwing me off, iron Vortecs better than Fastburns?
A friend of mine has a set of slightly used Fastburn heads he wants to sell me. Current motor specs are in the sig. As-is, with my HSR, cam and iron Vortecs, Im looking at 413hp@5500 and 443ft-lbs@4000. When I put in the numbers for the Fastburns, it says 357hp@5000 and 426ft-lbs@4000. I emailed Comp Caps and asked them if the XE274 would work with my HSR and iron Vortecs, and if it would also work if I swapped over to the Fastburns. They said the cam that I got should be fine with both applications. Would these heads not be worth it? Or would it be best to swap to a different NON-ROLLER cam if I did get the FB? Id like to pass, but if I could get a pretty decent gain Id like to go for it. But from my numbers Id be losing 56hp and 17ft-lbs!
10-06-2008, 01:41 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
A friend of mine has a set of slightly used Fastburn heads he wants to sell me. Current motor specs are in the sig. As-is, with my HSR, cam and iron Vortecs, Im looking at 413hp@5500 and 443ft-lbs@4000. When I put in the numbers for the Fastburns, it says 357hp@5000 and 426ft-lbs@4000. I emailed Comp Caps and asked them if the XE274 would work with my HSR and iron Vortecs, and if it would also work if I swapped over to the Fastburns. They said the cam that I got should be fine with both applications. Would these heads not be worth it? Or would it be best to swap to a different NON-ROLLER cam if I did get the FB? Id like to pass, but if I could get a pretty decent gain Id like to go for it. But from my numbers Id be losing 56hp and 17ft-lbs!
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10-06-2008, 02:29 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
How much of a "deal" is he giving you? The fastburn is a better head than the vortec. The vortec head is more of a production head as where the fastburn is a performance head. I don't have any raw numbers though.
You'd probably want to match a cam to the heads if you get them.
You'd probably want to match a cam to the heads if you get them.
10-06-2008, 02:57 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
How much of a "deal" is he giving you? The fastburn is a better head than the vortec. The vortec head is more of a production head as where the fastburn is a performance head. I don't have any raw numbers though.
You'd probably want to match a cam to the heads if you get them.
You'd probably want to match a cam to the heads if you get them.
-- Joe
10-06-2008, 03:44 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
Agreed
...But the Fastburns by far hold more potential than the vortecs. Vortecs are pretty good from the factory. You can't gain a whole lot by porting. Sure you can gain some, but not a ton (according to Chevy High Performance).
...But the Fastburns by far hold more potential than the vortecs. Vortecs are pretty good from the factory. You can't gain a whole lot by porting. Sure you can gain some, but not a ton (according to Chevy High Performance).
10-06-2008, 06:49 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
I ported out the exhaust ports because I had planned on some future nitrous use, which I doubt Ill do now.
As far as the numbers, I don't have any in front of me. But just from going on what Comp told me (that the cam will be good with either setup), and DD2k, I dont know how it's coming up with the numbers that it is. From what I've read, the Fastburns get their power from better flame travel in the combustion chamber, not necessarily flow numbers. I also seem to remember seeing somewhere that the bowtie Vortecs have about the same power curve as the FB.
ah hah! I found a very useful page, Im gonna bookmark this one. It's got all kinds of flow bench numbers on GM heads. From what I can tell, the L31s flow SLIGHTLY less than the FB until .500" lift, which is about where Im at right now with my cam. I have no idea how to interpret these into meaningful terms, so if yall could help me out, Id appreciate it!
http://purplesagetradingpost.com/sum...%20Fast%20Burn
As far as the numbers, I don't have any in front of me. But just from going on what Comp told me (that the cam will be good with either setup), and DD2k, I dont know how it's coming up with the numbers that it is. From what I've read, the Fastburns get their power from better flame travel in the combustion chamber, not necessarily flow numbers. I also seem to remember seeing somewhere that the bowtie Vortecs have about the same power curve as the FB.
ah hah! I found a very useful page, Im gonna bookmark this one. It's got all kinds of flow bench numbers on GM heads. From what I can tell, the L31s flow SLIGHTLY less than the FB until .500" lift, which is about where Im at right now with my cam. I have no idea how to interpret these into meaningful terms, so if yall could help me out, Id appreciate it!
http://purplesagetradingpost.com/sum...%20Fast%20Burn
10-06-2008, 08:34 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
I ported out the exhaust ports because I had planned on some future nitrous use, which I doubt Ill do now.
As far as the numbers, I don't have any in front of me. But just from going on what Comp told me (that the cam will be good with either setup), and DD2k, I dont know how it's coming up with the numbers that it is. From what I've read, the Fastburns get their power from better flame travel in the combustion chamber, not necessarily flow numbers. I also seem to remember seeing somewhere that the bowtie Vortecs have about the same power curve as the FB.
ah hah! I found a very useful page, Im gonna bookmark this one. It's got all kinds of flow bench numbers on GM heads. From what I can tell, the L31s flow SLIGHTLY less than the FB until .500" lift, which is about where Im at right now with my cam. I have no idea how to interpret these into meaningful terms, so if yall could help me out, Id appreciate it!
http://purplesagetradingpost.com/sum...%20Fast%20Burn
As far as the numbers, I don't have any in front of me. But just from going on what Comp told me (that the cam will be good with either setup), and DD2k, I dont know how it's coming up with the numbers that it is. From what I've read, the Fastburns get their power from better flame travel in the combustion chamber, not necessarily flow numbers. I also seem to remember seeing somewhere that the bowtie Vortecs have about the same power curve as the FB.
ah hah! I found a very useful page, Im gonna bookmark this one. It's got all kinds of flow bench numbers on GM heads. From what I can tell, the L31s flow SLIGHTLY less than the FB until .500" lift, which is about where Im at right now with my cam. I have no idea how to interpret these into meaningful terms, so if yall could help me out, Id appreciate it!
http://purplesagetradingpost.com/sum...%20Fast%20Burn
The Fastburn is a performance head. It's meant to perform at it's fullest potential with a high lift, big duration cam. That's why you see it come alive at a greater lift. The vortec head is simply a factory head, made for use with factory peanut cams.
Don't get me wrong, the vortecs flow well, but they aren't meant to be high revving race heads. The Fastburns take more of a step in this direction.
Also, the Fastburns have a larger intake runner which would be beneficial for your 383.
You can't really go off of the desktop dyno in my opinion.
Found this on a site:
Both the AFR's and the Fast Burn heads are winners. The AFR's should outflow the FB in raw cfm, however the FB should have better swirl characteristics.
In the GM Performance Parts catolog it says "When tested on a 383 ci small block engine with 9.5 to 1 compression ratio and .540" lift roller cam, single plane intake manifold and 750 cfm Holley carburator, the Fast Burn heads produced 497 hp at an incredibly low 5,800 rpm".
For those interested in some of the most likely ingredients in the GMPP fast Burn 383, follow along: cam #12370847, intake #12496822 (Eliminator Vortec).
In the GM Performance Parts catolog it says "When tested on a 383 ci small block engine with 9.5 to 1 compression ratio and .540" lift roller cam, single plane intake manifold and 750 cfm Holley carburator, the Fast Burn heads produced 497 hp at an incredibly low 5,800 rpm".
For those interested in some of the most likely ingredients in the GMPP fast Burn 383, follow along: cam #12370847, intake #12496822 (Eliminator Vortec).
The 497hp 383 example in the catalog used FB heads that had been cleaned up a little (not radically ported)...this was done without my knowledge and I didn't find out until after the catalog was printed. Also the cam had alot of duration, which is required anytime you try to feed a 383 or 400 inch engine due to the increased piston speed and long stroke and the effects they have on cylinder fill. The cam was not the one listed in the catalog. Just read what I wrote, sounds like I'm making excuses. I'm not, just don't want anyone to be disapointed. Stock FB heads and the 540 lift cam in the catalog, with 9.6 CR, 4.0" bore, 3.8" stroke, dual plane vortec intake, 750cfm Holley will make 440 hp at about 5800 and 450 ft lbs at 4000.
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10-06-2008, 09:10 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
There's no such thing as a universally good head. You choose your head for a particular application.
10-08-2008, 08:57 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
Can any of yall recommend a better cam other then the XE274? My motor specs are in the sig, I would assume something that's a little more forgiving for EFI tuning, maybe the same duration but with more lift. Id like to stay with the hyd. flat tappet setup, dont wanna go roller just yet. CC 280XFI looks like it may be a good match
EDIT: I cannot find a .cam file for the 280 for DD2k, so I can't really tell if mathematically it would be the right choice. Id like for the max RPM of the motor to be right around 6k rpm. Any suggestions? I haven't shopped for cams in years, and I got lucky that I picked the xe274 considering how well it's been with my current setup.
EDIT: I cannot find a .cam file for the 280 for DD2k, so I can't really tell if mathematically it would be the right choice. Id like for the max RPM of the motor to be right around 6k rpm. Any suggestions? I haven't shopped for cams in years, and I got lucky that I picked the xe274 considering how well it's been with my current setup.
Last edited by spills; 10-08-2008 at 09:31 PM.
10-12-2008, 08:01 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
well, I thought I found a winner. I found some more .cam files for DD2k, and it looks like the XR288HR would bank me about 449hp and 483ft-lbs. However, I knew roller cams were expensive, but damn! Plus this cam's got a 110 LSA, which Im trying to avoid. I was looking at the 280XFI, with 1.5 rockers (from my math) it would be about .540" I and .534" E lift, 230/236 @ .050" 113LSA. Anyone know of a flat tappet cam that might yield me 420hp and 450 ft lbs that's got about a 113LSA?
I was just on Crane's website emailing them to see what they think, and in the contact form it says "NOTE: Computer Controlled Vehicles Must Use Smooth Idle Camshafts ONLY", Why is this? Ive heard several LS1 F-bodys and plenty of Vettes and Mustangs with really rough idles that are computer controlled
I was just on Crane's website emailing them to see what they think, and in the contact form it says "NOTE: Computer Controlled Vehicles Must Use Smooth Idle Camshafts ONLY", Why is this? Ive heard several LS1 F-bodys and plenty of Vettes and Mustangs with really rough idles that are computer controlled
Last edited by spills; 10-12-2008 at 08:07 PM.
10-12-2008, 08:43 PM
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Re: DD2K throwing me off, iron Vortecs better than Fastburns?
I was just on Crane's website emailing them to see what they think, and in the contact form it says "NOTE: Computer Controlled Vehicles Must Use Smooth Idle Camshafts ONLY", Why is this? Ive heard several LS1 F-bodys and plenty of Vettes and Mustangs with really rough idles that are computer controlled
Not a big deal, and there is a TON of guys who will lend advice. There is a few guys on here with 10 second EFI cars so if they can do it, so can you.
-- Joe
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