AFR LS1 205cc
 

Just saw this in Feb Hot Rod mag.
Flow numbers for the AFR 205-not sure if they are as cast or cnc ported
AFR ---------------- LS1---------------Ls6 -----------GMPP LS6
.200---144/116-------136/108 -----------137/116-----------142/113
.300---208/170-------196/145------------188/153-----------209/156
.400---255/206-------217/170------------233/175-----------257/189
.500---287/221-------224/186------------260/193-----------283/220
.550---296/227-------227/192------------245/227-----------286/199
.600---302/232-------230/198------------245/200---------- 287/231
.650---304/236-------233/200------------245/202-----------289/233
4.125 bore fixture and 1.875 flow tube

How does that compare to ls6 stage II's ?

Does anyone know the flow numbers on a standard LS1 bore size? Why the heck did they flow them on a 4.125 bore? That's not a good standard for comparison at all.

Hmm, how much more can they get out of those? My 5.7 LS1 heads flowed 337 cfm @ .600" on the intake, doesn't look like the AFR's will be worth the money :confused:

That is what I was thinking. Intake numbers look OK, mid lift numbers look good, but exhaust numbers leave some to be desired.

Ditto!

you've got to look at the port volume too. 205 is damn small.

Gomer I totally agree. Flowing on a 4.125 bore with the 205 heads is very deceiving because those 205 heads are suppose to be for stock cubed motors up to around 400CI motors. They should have flowed them on a 3.905 bore.

Linear whose heads are those that flowed 337??? I have NEVER seen a set flow that much on a 3.905 or 4.00 bore. Never mind!!! I see you have a big bore motor!!!!!

I got the heads through AAP, the actual porter's are Race Prep Engineering, thy know their stuff. My buddy Micah's 6.0 heads flowed 342 cfm on a stock 3.90" bore :eek2:

I'm curious to see the stock LS1 and LS6 numbers, for comparison to the AFR's, and also if those were as-cast or CNC'd numbers.

I have to admit, I'm a bit nonplussed by those numbers as well. Might feel OK about not spending a million bucks on heads after all...

-Jake

Definitly need to compare against numbers on the same bench to figure out if they are impressive or not. The stock head numbers would maybe help give us a baseline as to how that flowbench/testing conditions compare.

every add i've seen for these heads they claim a 75HP increase over stock....that's insane

the flow numbers your seeing on the 205 is the CNC ported ones. They need to post the 200 as cast heads flow numbers.

You are all forgetting about the 200/205cc port volume on the AFR's. More velocity!

Arent all the popular porters around 220cc or so port volume?

AFR also makes a 220cc head. so if the 205 head flows 302/232 at .600 lft imagine what the 220 would flow!

i added the stock LS1 and Ls6 to the original post. The add also mentions that the AFR's cross section in the intake port is 30% smaller than the ported GMPP.(more velocity) And that the AFR's have a raised short turn radius for better flow to the back of the valve

BUT that 302/232 is on a 4.125 bore. That totally skews the numbers. The difference in flow between a 3.905 and 4.125 bore is substantial. Published numbers like that are good for one thing.. selling heads to people that don't know any better. Is there ANY numbers out on these heads being flowed on a 3.905 bore?

AFR has been great in the industry. My flow numbers off of my Stage II LS6 heads (2.02/1.57 valves) flow better than those 4.125" bore heads..if they have the big valves the intake should be more like 360 @ 600. Howerver AFR knows a lot more about heads than I do. I trust thier product..it will be nice to see what kind of dyno numbers they get out of those heads....remember our intakes only flow so much..so whats the use until we free up that restriction.

Yeah, need to get a sponsor or something to set up a flowbench, with a set of each heads, same bench, bore, pipe etc.....and then see numbers. But right on about smaller port, and velocity.

I think you guy's might be jumping on the wrong part here..Those AFR flow #'s with only 205cc ports is awesome,if true..My Ported LS6's flow alittle more but the port is 221cc.(stock is 215cc)..By the way it looks,346's with these heads will kick ass across the rev range over stage 2 ported heads due to the velocity....
I wish they will hurry up and release them so we can stop debating and find the facts!!!!!