AFR 76cc head questions
Thread Starter
Joined: Nov 2001
Posts: 45,325
Likes: 1,767
From: Chicago, IL
AFR 76cc head questions If someone was running a 3.910 bore LS6 block like me, I am thinking the AFR 205's would make more sense than say the 225's. Thoughts?
My current 6.0 heads had to be repaired last time and I can't see running past this season with them.
What do the AFR 76cc heads flow?
Could I use a .100 longer valve instead (from them)?
My current 6.0 heads had to be repaired last time and I can't see running past this season with them.
What do the AFR 76cc heads flow?
Could I use a .100 longer valve instead (from them)?
Basicially from what i gather, the 225 will make more power on a stock bore if compression were the same.
Seeing as your a FI guy I dont know what gains would be made but for 300 dollars I would defentially try it out.
Hell maybe you could swap heads and go with a 388 all bore at the same time.
Hope this helps at least a bit.
Seeing as your a FI guy I dont know what gains would be made but for 300 dollars I would defentially try it out.
Hell maybe you could swap heads and go with a 388 all bore at the same time.
Hope this helps at least a bit.
from what Tony Mamo told me the large chamber 205's never went into full production if at all. because i wanted a set myself. the 72cc 225 is your only option w/ the 4.1xx gasket.
Hello John,
From what Tony has stated, the 225's are more likely a better head for your application. Several guys I've talked with said these good heads can be further improved by a little port work on the exhaust side for FI usage. Regarding flow #'s I've asked and the question seems to be avoided. Overall this it probably the best head for the $ today, but I suspect that could change before next season.
I'm in the same boat looking for good FI heads, I'm thinking about the new ET Performance heads as well. You might want to at least talk with ET.
Let me know what you decide to do...
From what Tony has stated, the 225's are more likely a better head for your application. Several guys I've talked with said these good heads can be further improved by a little port work on the exhaust side for FI usage. Regarding flow #'s I've asked and the question seems to be avoided. Overall this it probably the best head for the $ today, but I suspect that could change before next season.
I'm in the same boat looking for good FI heads, I'm thinking about the new ET Performance heads as well. You might want to at least talk with ET.
Let me know what you decide to do...
Thread Starter
Joined: Nov 2001
Posts: 45,325
Likes: 1,767
From: Chicago, IL
I don't have any plans to run more cubes, I can see maybe at some point building a LS2 based engine but I'm looking to go 9.25-8.99 this year with the current 348ci.
Would the 225's be too much for a 348ci? At what point would the port velocity be an issue?
Any ball park flow numbers? My 6.0's flow like 299/219, with 2.05/1.60 valves that were cut down to fit the stock seats. I'm running a .100 longer Manley SD valve setup so I could get the right installed heighth for my springs.
Would the 225's be too much for a 348ci? At what point would the port velocity be an issue?
Any ball park flow numbers? My 6.0's flow like 299/219, with 2.05/1.60 valves that were cut down to fit the stock seats. I'm running a .100 longer Manley SD valve setup so I could get the right installed heighth for my springs.
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
these are the advertised flow #s
And these are the specs:
Basic Package Components
100% CNC Ported Combustion Chambers
100% CNC Ported Exhaust Ports
100% CNC Ported Intake Ports
3-angle Raduised Valve Job
Intake Valve, 2.080” standard length #7208
Exhaust Valve, 1.600” standard length #7228
1.290” O.D. Dual Hydraulic Valve Spring, 135 lbs. on seat, .600” maximum lift (upgrades available) #8017
7º 1.250 Titanium Retainers #8512
7º Valve Locks #9007
Valve Seals #6612
Spring Cup #8042
Intake Valve Seats #9059
Exhaust Valve Seats #9069
Bronze Valve Guides #9051
Specifications, Features, and Supporting Components
Head Torque 11MM ARP 70 FT lbs w/ Moly 8mm 23 FT lbs w/ Moly
Exhaust Port Gasket GM#12558573/ Fel-Pro #1440 AFR#6859
Intake Port Volume (as cast) 220cc
Intake Valve Size 2.080
Exhaust Port Volume (as cast) 78cc
Head Gasket GM#12498543 or 12498544, Fel-Pro#1041, AFR#6847
Cometic AFR #6846
Head Bolts & Studs Standard ARP, AFR #6330, #6331 & #6332
Head Bolt Washers Standard ARP, AFR #6328 & #6329
Jesel or TD Shaft Mount
Suggested Manifold LS6, FAST or TPIS
Accessory Holes Are Pre Drilled
Spark Plug Starting Range AC 41-974 Platinum
Combustion Chambers 66cc or 76cc
Spring Pocket 1.450 O.D can be machined to 1.550 O.D.
Valve Spacing Stock
Rocker Arms Location Stock
Valve Angle Stock
Angle Mill (milling available) .008” per cc
Flat Mill (milling available) .006” per cc
Note: Milling head deck will affect flow numbers
Trending Topics
Thread Starter
Joined: Nov 2001
Posts: 45,325
Likes: 1,767
From: Chicago, IL
Oh cool thanks. I'm running a 600 lift cam so I like the look of those numbers, especially on the exhaust side. I can't see running a 2.08 intake valve but I can do more research.
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225's all the way John....
Completely a no brainer.
Also, for people questioning AFR 225 exhaust flow, take a look at all my independent test results...An AFR 225 is the 2nd best flowing head on the exhaust side (only considering the "peak" .600 #) of ANY head I have ever had on my bench. The highest flowing head did not have the area under the curve, was significantly larger (5 cc's....huge difference on an exh. port), and only outflowed the 225 by one or two CFM at the .600 mark.
Bottom line is the 225 head is outstanding for a FI or turbo buildup right out of the box....save your money on the "tune up"....there's a greater chance you will hurt it than help it (you might increase the peak #'s a few CFM by making it larger but end up killing all the flow till .400 lift etc. if not done properly...essentially killing some of the ports efficiency).
Hope this helps...
Tony M.
PS....Give me a call at AFR if you need further clarification or have some other questions.
Completely a no brainer.
Also, for people questioning AFR 225 exhaust flow, take a look at all my independent test results...An AFR 225 is the 2nd best flowing head on the exhaust side (only considering the "peak" .600 #) of ANY head I have ever had on my bench. The highest flowing head did not have the area under the curve, was significantly larger (5 cc's....huge difference on an exh. port), and only outflowed the 225 by one or two CFM at the .600 mark.
Bottom line is the 225 head is outstanding for a FI or turbo buildup right out of the box....save your money on the "tune up"....there's a greater chance you will hurt it than help it (you might increase the peak #'s a few CFM by making it larger but end up killing all the flow till .400 lift etc. if not done properly...essentially killing some of the ports efficiency).
Hope this helps...
Tony M.
PS....Give me a call at AFR if you need further clarification or have some other questions.
Thread Starter
Joined: Nov 2001
Posts: 45,325
Likes: 1,767
From: Chicago, IL
Wow interesting information. So basically the AFR 225's are really good out of the box. If/when folks do supplemental porting, what areas are they hitting and why?
I know that the 205's have been independently flowed and they are all right where they are advertised to be.
I know that the 205's have been independently flowed and they are all right where they are advertised to be.
Originally Posted by Pro Stock John
Wow interesting information. So basically the AFR 225's are really good out of the box. If/when folks do supplemental porting, what areas are they hitting and why?
I know that the 205's have been independently flowed and they are all right where they are advertised to be.
I know that the 205's have been independently flowed and they are all right where they are advertised to be.
https://ls1tech.com/forums/generation-iii-internal-engine/317323-interesting-flow-data-long-thread.html
PLENTY of info to look over and get an idea of where the 225 (and 205) heads fair (out of the box) based on what I have seen thus far. That test only represents the larger stuff I have tested. I omitted quite a few heads that would have skewed the averages lower.
Give me a call when you have some time.
From the tesing we've done the AFR head has kicked *** over the competition in the FI world.We've pushed the 205 head with a 220 Cam on a 346 over 700hp with 14lbs and pump gas.
After talking to Tony awhile ago we got a set of 225's for our next 346 FI project.This is a 9-1 compression 346 with a 224 Cam,AFR 225's and being fed from a F1 Procharger.Should be finished next week
I would expect some nasty #'s from this beast while retaining complete stockish drivability 
After talking to Tony awhile ago we got a set of 225's for our next 346 FI project.This is a 9-1 compression 346 with a 224 Cam,AFR 225's and being fed from a F1 Procharger.Should be finished next week
I would expect some nasty #'s from this beast while retaining complete stockish drivability 