Trick flow Double Hump alloy heads

[steve cowan]

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[steve cowan]

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Flow numbers are without intake manifold
The numbers go backwards after 500" lift but the port was not noisy
Have not tested exhaust yet hopefully tomorrow.
I am scratching my head on one thing-
The victor jnr fits real nice and was used on my cast iron Darts,
The intake flow increased slightly with manifold fitted,I ran the test twice with same results, has anyone else seen this before?
From my limited experience I have always had flow loss of around 6% with a ported intake.

[steve cowan]

Purchased a new 880 roller block yesterday
4" bore photos are to show the shrouding,
I checked cylinder wall thickness everywhere I could and was pretty happy to find 0.230" - 0.250" until I got to #6 cylinder 0.150"
Funny because I have 3 x 010 early blocks with cracked head bolts and sleeves in #6 cylinder, is this a known casting flaw from the factory???
Block is going 0.030" over .

[mtrhead]

Steve
Be really interested in the capabilities of this casting
Would be cool if it could flow in the 290s and make 600* Hp
And be made to look original

TFS was advertising 200cc CNC versions last year. COVID must of delayed?

[ClassAct]

20211003_131504.jpg20211003_121332.jpg20211003_121315.jpg20211003_120951.jpg
Flow numbers are without intake manifold
The numbers go backwards after 500" lift but the port was not noisy
Have not tested exhaust yet hopefully tomorrow.
I am scratching my head on one thing-
The victor jnr fits real nice and was used on my cast iron Darts,
The intake flow increased slightly with manifold fitted,I ran the test twice with same results, has anyone else seen this before?
From my limited experience I have always had flow loss of around 6% with a ported intake.

Are you going to flow test the heads with the manifold on? I’d like to see those results.

[RevTheory]

Purchased a new 880 roller block yesterday
4" bore photos are to show the shrouding,
I checked cylinder wall thickness everywhere I could and was pretty happy to find 0.230" - 0.250" until I got to #6 cylinder 0.150"
Funny because I have 3 x 010 early blocks with cracked head bolts and sleeves in #6 cylinder, is this a known casting flaw from the factory???
Block is going 0.030" over .

Vizard said he split a cylinder wall on 3 880s in a row at +.030 right around the 500 hp mark. He never said what cylinders though. I've got one in the garage that I'm hesitant to use, at least not without a thorough sonic check.

I can't say I'm diggin' the shrouding. Are you going to notch the bores?

[steve cowan]

20211003_131504.jpg20211003_121332.jpg20211003_121315.jpg20211003_120951.jpg
Flow numbers are without intake manifold
The numbers go backwards after 500" lift but the port was not noisy
Have not tested exhaust yet hopefully tomorrow.
I am scratching my head on one thing-
The victor jnr fits real nice and was used on my cast iron Darts,
The intake flow increased slightly with manifold fitted,I ran the test twice with same results, has anyone else seen this before?
From my limited experience I have always had flow loss of around 6% with a ported intake.

Are you going to flow test the heads with the manifold on? I’d like to see those results.

I want to re- test today,I am a little confused with increased numbers.
Adding a intake manifold is Adding a restriction if tested at same depression so I can't see why flow numbers increased
Would be nice to probe around the pinch area with manifold fitted to see if air has move up towards the roof more.

[steve cowan]

Purchased a new 880 roller block yesterday
4" bore photos are to show the shrouding,
I checked cylinder wall thickness everywhere I could and was pretty happy to find 0.230" - 0.250" until I got to #6 cylinder 0.150"
Funny because I have 3 x 010 early blocks with cracked head bolts and sleeves in #6 cylinder, is this a known casting flaw from the factory???
Block is going 0.030" over .

Vizard said he split a cylinder wall on 3 880s in a row at +.030 right around the 500 hp mark. He never said what cylinders though. I've got one in the garage that I'm hesitant to use, at least not without a thorough sonic check.

I can't say I'm diggin' the shrouding. Are you going to notch the bores?

I thought of buying pistons $1200 AU and keeping it a 4" bore,there is pitted rust on #2,4,6,8 was going to run the dingle hone through and look .
The block will go to machine shop to get deck height done,recheck mains,lifter bores etc.
I can get 1/16" , 1/16" , 3/16" dished pistons that would lower compression down .
Also considered 1.94" - 1.5" valves as well as I have a few sets but will put the throats at 92% respectively.
Might work with steeper seat 50 deg ?
It also could be a silly move for the application.
The other thing is the chamber hangs over the bore by a fair amount on the intake side,I have not notched bores since my 6 cylinder days as a kid,might look into it as well.
All this stuff is getting ridiculous expensive-
I bought a Dart little M sportsman 18 months ago AU $2600 now they are AU $4500
this junk 880 block cost me AU $2500 and I can pick it up one handed the Dart block can't even get it off the ground

[MadBill]

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Flow numbers are without intake manifold
The numbers go backwards after 500" lift but the port was not noisy
Have not tested exhaust yet hopefully tomorrow.
I am scratching my head on one thing-
The victor jnr fits real nice and was used on my cast iron Darts,
The intake flow increased slightly with manifold fitted,I ran the test twice with same results, has anyone else seen this before?
From my limited experience I have always had flow loss of around 6% with a ported intake.

Are you going to flow test the heads with the manifold on? I’d like to see those results.

I want to re- test today,I am a little confused with increased numbers.
Adding a intake manifold is Adding a restriction if tested at same depression so I can't see why flow numbers increased
Would be nice to probe around the pinch area with manifold fitted to see if air has move up towards the roof more.

Of course everyone fits some kind of radiused entry at the port flange, but to flow less with it than with the manifold suggests it is lacking somehow. (Or maybe the manifold just aims the flow in a more optimum direction.)

[GARY C]

I have a feeling that head is going to port out quite nicely. Anyone know how those heads compare to AFR's Enforcer?

https://www.speedwaymotors.com/Chevy-SB ... eb28_2020)
Bare
https://www.speedwaymotors.com/Chevy-SB ... 79620.html

[steve cowan]

Are you going to flow test the heads with the manifold on? I’d like to see those results.

I want to re- test today,I am a little confused with increased numbers.
Adding a intake manifold is Adding a restriction if tested at same depression so I can't see why flow numbers increased
Would be nice to probe around the pinch area with manifold fitted to see if air has move up towards the roof more.

Of course everyone fits some kind of radiused entry at the port flange, but to flow less with it than with the manifold suggests it is lacking somehow. (Or maybe the manifold just aims the flow in a more optimum direction.)

You are correct on both fronts Bill
Had a phone conversation with a well known speedtalk engine builder.
Basically the port is turbulent because flow numbers go down after about 500" lift
Velocity at apex is 450ft/sec @28".even though it is not noisy as in popping sound that I am familiar with,the air can't turn correctly, the manifold calms the air so to speak as you have mentioned.
I figured my testing was flawed with increased numbers but in this case it may not be so.

[steve cowan]

I have a feeling that head is going to port out quite nicely. Anyone know how those heads compare to AFR's Enforcer?

https://www.speedwaymotors.com/Chevy-SB ... eb28_2020)
Bare
https://www.speedwaymotors.com/Chevy-SB ... 79620.html

Each bare head cost me $1000 AU landed to my door.

[steve cowan]

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This is with manifold bolted up.
This is the first time I have seen flow numbers increase hence my initial confusion.
Velocity is ft/sec at the runner opening on intake bolted to head.
The Vic jnr has a avg csa of approx 2.3" in the runner.

[steve cowan]

Exhaust numbers for anyone who looks at them,short pipe used,
Numbers converted to 28" test pressure.
A bit choppy down low lift but port sounds very reasonable.
Won't take alot to get cross sections where they need to be.

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[Fatman]

20211003_131504.jpg20211003_121332.jpg20211003_121315.jpg20211003_120951.jpg
Flow numbers are without intake manifold
The numbers go backwards after 500" lift but the port was not noisy
Have not tested exhaust yet hopefully tomorrow.
I am scratching my head on one thing-
The victor jnr fits real nice and was used on my cast iron Darts,
The intake flow increased slightly with manifold fitted,I ran the test twice with same results, has anyone else seen this before?
From my limited experience I have always had flow loss of around 6% with a ported intake.

Are you going to flow test the heads with the manifold on? I’d like to see those results.

I want to re- test today,I am a little confused with increased numbers.
Adding a intake manifold is Adding a restriction if tested at same depression so I can't see why flow numbers increased
Would be nice to probe around the pinch area with manifold fitted to see if air has move up towards the roof more.

2V clevelands can do this. Turbulent flow from about .450" up but quietens down/stabilises once a manifold is bolted on.