It had to happen.
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From: Sonoma Co. Ca.
Thread Starter
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From: Sonoma Co. Ca.
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From: Central Cal.
Knowing AFR and their capabilities, I was kinda hoping a 245cc would happen, as it would possibly flow as much or a little more than the OEM head, which would increase flow velocity a BUNCH over stock, thereby kicking low-end torque up a BUNCH.
But that's just me.... lol
But that's just me.... lol
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From: Central Cal.
Hey, AFR does many different cathedral heads, so maybe variations of this one are coming down the chute too. Someday....
I think a 245 would give a stock LS3 a much needed low end kick. Couple that with a conservative cam, and a sleeper is born!
I think a 245 would give a stock LS3 a much needed low end kick. Couple that with a conservative cam, and a sleeper is born!
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From: Mississippi
I personally think runner sizes are overated when it comes to selecting the cylinder heads. I go by real world results instead of what a salesman say.....
Its a guy on here running a ERL 427ci motor in a heavy GT0 running 10s naturally aspirated with AFR 205 heads and a Fast 92mm intake .... 230s on the cam. On paper the AFR head dont look like it have enough to support a 400 plus cube motor but again track results never lie.
Bigger the port the lazier the head becomes as far as air speed and throttle response.
Hell Tony Mamo 454ci motor did great with a cathedral 245cc head. So did Tooleys. Tooley 454ci motor went 9s naturally aspirated.
I was inform on Tuesday by a well respected guy that spec cams for a living about cylinder heads. He shows no favoritism at all!! He basically said when running a rectangle head you need a single plane intake to take advantage of thr largr intake runners. No need in running a big head if you not go let the engine breath/rev high.
Its a guy on here running a ERL 427ci motor in a heavy GT0 running 10s naturally aspirated with AFR 205 heads and a Fast 92mm intake .... 230s on the cam. On paper the AFR head dont look like it have enough to support a 400 plus cube motor but again track results never lie.
Bigger the port the lazier the head becomes as far as air speed and throttle response.
Hell Tony Mamo 454ci motor did great with a cathedral 245cc head. So did Tooleys. Tooley 454ci motor went 9s naturally aspirated.
I was inform on Tuesday by a well respected guy that spec cams for a living about cylinder heads. He shows no favoritism at all!! He basically said when running a rectangle head you need a single plane intake to take advantage of thr largr intake runners. No need in running a big head if you not go let the engine breath/rev high.
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From: Central Cal.
You're right! It's about getting a small runner volume to flow huge numbers, like this new LS3 head. The runner is 260cc's exactly stock size, but it flows WAY more than stock, which means flow velocity has to be huge, which contributes to low and mid-range power. This head should do well!
You're right! It's about getting a small runner volume to flow huge numbers, like this new LS3 head. The runner is 260cc's exactly stock size, but it flows WAY more than stock, which means flow velocity has to be huge, which contributes to low and mid-range power. This head should do well!
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From: Central Cal.
Which then sounds like it would "slow the flow". With the 12*valve angle, is the port then shorter? Then, with the same volume, it would be "fatter" compared to stock. Not as good as I thought.
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From: over dere
Knowing AFR and their capabilities, I was kinda hoping a 245cc would happen, as it would possibly flow as much or a little more than the OEM head, which would increase flow velocity a BUNCH over stock, thereby kicking low-end torque up a BUNCH.
But that's just me.... lol
But that's just me.... lol
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From: Central Cal.
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From: over dere
I think they're one of the best flowing 3.89 bore heads out there. But yes mast tends to advertise flow numbers on the bore they're designed for. And the 240 mast heads will still outflow stock ls3 heads by a lot
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From: Central Cal.
They are good heads! AND they're awfully proud of them! lol
Yeah it makes sense to flow on the intended bore. Truth in advertising! If it were possible to flow a stock head on a small bore, it would not show good numbers either.
Yeah it makes sense to flow on the intended bore. Truth in advertising! If it were possible to flow a stock head on a small bore, it would not show good numbers either.
Yeah, generally speaking, but at some point you have to increase the CSA to get the flow numbers that you're after. At 28" of H20, where most flow tests are done, you aren't going to get more than 145CFM per square inch.
If I had to guess, I would think it would be a little longer. With the valve laying flatter to the deck at 12 degree versus 15 degrees, the backside of the port would get longer. It just depends on what axis the valve is rotated on.
They probably shrunk the port in key areas that may have been dead spots, which are areas in the port where there isn't a whole lot going on. You can fill in these areas without hurting flow or causing excessively high velocity.
If I had to guess, I would think it would be a little longer. With the valve laying flatter to the deck at 12 degree versus 15 degrees, the backside of the port would get longer. It just depends on what axis the valve is rotated on.
They probably shrunk the port in key areas that may have been dead spots, which are areas in the port where there isn't a whole lot going on. You can fill in these areas without hurting flow or causing excessively high velocity.
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From: Central Cal.
Thank you KCS! Yeah, maybe I was backwards on the port/angle relationship. An incredible amount of science goes into head design, and it is fascinating to see how it all works together. I haven't seen AFR screw too many things up lately, so it will be interesting to see how the long-awaited LS3 head does.
Last edited by G Atsma; May 4, 2017 at 02:34 PM.
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