Larry, I am off all the way thru the lift curve compared to your numbers even after figuring for the smaller size valve. Those are some impressive numbers for that head. I wish I could have a look at the chamber and SSR on those. lol.
What is the difference between the first #034 head and the later ones they called bowtie II's? The ones I am working on are the later ones I think.
i have a few Pics i can post later
also have a brand new #034 head band-sawed into different sections
i'll take a few closeup Pics of cut aways, and aluminum templates
the 1st time i saw the #034 cast-iron Bowtie was at Brodix in Mena, Ark
Mr. J.V. Brotherton was giving me a tour of Brodix
and there was a cut-away section of #034 head
i asked what a GM cast-iron head was doing at Brodix ???
He said not to tell anyone, it was top secret, and the Head would be released soon to the Public
i guess its been long enough time now to tell about it .
even have a Pic i can post of that head sitting at Brodix , i'll post it later.
here's a Link to Head casting at Brodix
http://www.maxracesoftware.com/casting_ ... r_head.htm
there are atleast 4 different versions of #034 castings
the 1st one i saw and ran, had thinner chamber wall thickness and wasn't kicked out on the exhaust side
2nd revision= thicker chamber walls + kicked-out waterjacket area on
exhaust side
3rd revision= basically same thing but now had a cast in indention at where the heat-riser location would be on the Intake flange
4th revision = the current head now..same as 2 & 3 , and i'll have to say more tomorrow about
When I flow at 28" and flow @ 40" now and convert back to 28" the numbers match nicely until the valve is >=.600". From .600" on up the higher depression will show less (converted back to 28") than when flowing at 28". Does this indicate the SSR is still a little turbulent at higher velocities or will this always happen at the higher depressions/velocities?
you've probably checked for leaks or leakage, especially when flowing at higher test pressures at lower lifts the exhaust valve can partially be sucked opened at high test pressures
whenever i flow the Intake Port i use a metal device to increase exh valve spring pressure, then just pop it off when i flow test the Exh port
as in this Link
http://www.maxracesoftware.com/Valve_Open_Fixture2.jpg
1 more thing, i always Flow Test with a HeadGasket and the Head is always bolted down to the Flow fixture.
on my SF-600 the Intake port will usually follow the standard pressure conversion equation all the way up to 48 inches
but i occasionally run into Heads that look great at 28" Inches, but fall off pretty much as test pressure is increased to 36 or 48 inches on the Intake side. Lately half the LS-6 or LS-1 heads people send me look OK at 28 inches , but when flow tested at 36" or higher fall off 5+ percent of flow sometimes at .500" lift and above...i usually redo the valve job, bowl, short turn and fix the problem, the result is they make more HP/TQ and continue to make good HP after peak HP, they don't fall off as quick and use sometimes a lot less fuel.
http://www.maxracesoftware.com/VinceFMSdyno.jpg
some of the LS-6 heads take a dive at .500" Lift and above, as early as 30 inches of test pressure , but look OK at 28" inches
if you flow only at 28" inches you'll never know ?
you should spot check Int ports as high in test pressure as you can
100 PerCent of the time in every Head i fixed this problem, the RaceCar has went faster down the DragStrip !!
on the exhaust side, i've seen where all 4 exh ports might Flow the very same Flow Curve and numbers at 28" inches ...but when Flow tested at 48" inches, 1 port might flow a bunch better, 2 might increase steadily, and 1 might be a Turkey, hardly no increase ....but thats not common, but should be spot checked when you Flow Heads.
so if you believe in the .55 Mach Theory ?
(as its been pretty accurate in your case)
614 fps = 86.042 inches of water test pressure
around 3.107 psi
enough velocity fps to give you 121.14 Ve % if things are right, less Ve% if not
130.0 Ve%= 4.4088 psi or 122.08 inches of water or 731.44 fps or .6554 Mach
if you've looked at some of the data in Philip H Smith's work with the Morrison Pressure Indicator, way back then he was seeing depressions as high 3 to 5 psi
i think we should be Flow Testing at least a minimum of 36"
and more like 60" inches or 105" inches would be better
28" inches = 350.3 fps approx half the speed of 700 fps or .627 Mach that a modern Engine can attain....so usually 28" inches is a good representation of what Flow -vs- HP the engine should make,
but i think the better method would be to Flow test at pressure differential the Engine sees. Besides flow testing at 28" on a SF-600 Bench is a pain sometimes, as you have to look downward behind the cyl head, especially if you bolted an Intake Manifold and Carb on the Head.
36" inches is more Eye Level, and where 28" was on the older SF-300 benches.
i'm planning to increase CFM capacity of my FlowBench to 1500 CFM and going all digital to flow at 60" inches or higher.
Any tricks to getting that mid lift flow you can divulge?
the #034 Head had HeadBolt .500" tubes pressed into between the Intake Port pair, and that divider wall was perfectly straight to the tube, sort of like a Brodix Supr Spec casting, roof was raised and maxed out as high as possible and retained .100" thickness all the way to the spring seat ..the Bowtie head likes this if done correctly., the width of the short turn was as wide as the valve od or at least 2.050 i'd have to look at my notes
