Heads flow number question
Thread Starter
Racer
Joined: Jan 2003
Posts: 360
Likes: 0
From: Sumter South Carolina
Heads flow number question
I've been researching and trying to find out the pros and cons to some aftermarket heads, and it seems like the flow numbers are pretty close. Now I know that the numbers can be influenced by what bench flow is used, but I'm trying to see if the AFR heads really are worth the extra money over AI or Lloyd Elliot heads. So here's what I pulled off of the respective websites:
AI - 200cc LT1 CNC = 275.1/187.7 @0.5
LLoyd Elliot - 205cc LT1 = 275/190 @
AFR 180cc LT1 "Eliminator" = 260/207 @0.5
First disclaimer, I know the AFRs are the 180cc, but I think that is the largest they offer in the LT1 casting. So, I'm comparing streetable LT1 heads (for a NA 350 LT1 limited to 11.5CR). With AI and LE, the price includes a cam; not so with AFRs. Any of you guys smart on aftermarket heads, please educate me.
AI - 200cc LT1 CNC = 275.1/187.7 @0.5
LLoyd Elliot - 205cc LT1 = 275/190 @
AFR 180cc LT1 "Eliminator" = 260/207 @0.5
First disclaimer, I know the AFRs are the 180cc, but I think that is the largest they offer in the LT1 casting. So, I'm comparing streetable LT1 heads (for a NA 350 LT1 limited to 11.5CR). With AI and LE, the price includes a cam; not so with AFRs. Any of you guys smart on aftermarket heads, please educate me.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Look at the lower lift numbers, that will tell you what you want. Big peak #s sell heads but dont necessarily mean they will make the most power across the board. IMO cant beat the aftermarket, worth the money.
Melting Slicks
Joined: Apr 2007
Posts: 2,616
Likes: 111
I am running the AFR/TPIS aluminum heads (replaced the original cast irons) on my 85. TPIS had the same type of head for the LT1. The advertised intake port volume was 187cc and the flow number was 258CFM at .500 with different chamber volumes from 50 to 54 cc. These heads make great power on my car and I am running a very mild ZZ9 roller cam. I've had them since 2004 with no issues and I can recommend them to you. The price was $1850 and I know there are cheaper aluminum heads out there, but the porting on these things are fantastic.
Thread Starter
Racer
Joined: Jan 2003
Posts: 360
Likes: 0
From: Sumter South Carolina
Thanks for the posts so far. This is what I'm looking for. Does anyone have some good reasons for why to go the AFR route? Also, with better breathing heads and valvetrain upgrade, what RPMs are you guys running with a stock bottom end?
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
They are totally worth it. Look at the low lift #s and the difference on exhaust, the ports dont compare. Thicker decks, better combsution chamber design, etc. More efficient+ More power.
When you can make bigger #s acriss the board with a smaller (intake runner size) youre making power. JMO
When you can make bigger #s acriss the board with a smaller (intake runner size) youre making power. JMO
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
They are totally worth it. Look at the low lift #s and the difference on exhaust, the ports dont compare. Thicker decks, better combsution chamber design, etc. More efficient+ More power.
When you can make bigger #s acriss the board with a smaller (intake runner size) youre making power. JMO
When you can make bigger #s acriss the board with a smaller (intake runner size) youre making power. JMO
AFR offers LT1/LT4 reverse cool heads all the way up to the 227cc and at one time offered a raised runner 215cc head that will absolutly destroy any conventional low port 23 degree head ever made(you can still find these used if you look hard enough).
The ported factory casting LE and AI offer flow well considering... but are not anywhere near what the aftermarket offers (AFR, Trick Flow, Dart, Brodix)once maxed out.
Will
Advanced
Joined: Jul 2004
Posts: 83
Likes: 0
From: Orlando Fl
I would definitely like to see a back to back dyno comparison of the Advanced Induction 200cc ported OEM heads vs the new AFR Eliminator.
I have been doing my homework on heads and the AI stuff is putting down crazy numbers on the dyno and at the track, even on bone stock bottom ends.
The general concensus was that the older 180 - 195cc AFR stuff could not match the highend ported stock heads, however I think the situation could be different now - with a lightened valve train to boot.
I have been doing my homework on heads and the AI stuff is putting down crazy numbers on the dyno and at the track, even on bone stock bottom ends.
The general concensus was that the older 180 - 195cc AFR stuff could not match the highend ported stock heads, however I think the situation could be different now - with a lightened valve train to boot.
Navigator
Joined: Jan 2008
Posts: 9
Likes: 0
Look at a pair of Patriot heads from whiteperformance.com I have a new set that are about to be put into service. They will accept both Gen1 and vortec intakes. They will accept center or perimeter valve cover bolts. I have a friend that runs them and loves them. They cost less than $1,000.00 with triple spring that are rated for .650 lift. Less than $900.00 for doble springs rated at .550 Great flow numbers to boot. They will far outflow any modified factory intake, and almost all aftermarket intakes that will fir under your hood.
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Racer
Joined: Dec 2004
Posts: 306
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I am running the AFR/TPIS aluminum heads (replaced the original cast irons) on my 85. TPIS had the same type of head for the LT1. The advertised intake port volume was 187cc and the flow number was 258CFM at .500 with different chamber volumes from 50 to 54 cc. These heads make great power on my car and I am running a very mild ZZ9 roller cam. I've had them since 2004 with no issues and I can recommend them to you. The price was $1850 and I know there are cheaper aluminum heads out there, but the porting on these things are fantastic.
