292 Turbo Head Flow Tests

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292 Turbo Head Flow Tests

Post by maxracesoftware »

#292 Turbo Head Flow Tests on 2 different Heads

this #292 Turbo Head is the same Head with severe sunken Intake and Exhaust seats
as in this related Topic here :
Chamber Mods vs Material Volume Removed Question
Post by skinny z
viewtopic.php?p=909652#p909652
Meaux_old_Turbo292_sunk_seats_50degVJ_Test3_Sept_5_2021.jpg
Turbo292_SunkenSeatsAfterPorting.jpg
Turbo292_SunkenSeats1024x768.jpg
Turbo292_SunkenSeats1024x1365.jpg
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Re: 292 Turbo Head Flow Tests

Post by maxracesoftware »

this #292 Turbo Head is from Benoit's 316cid C/ED in the 1980's
originally had 2.035/1.600 Valve Combo

i just cleaned it up + new Valve Job + new larger 2.055/1.600 Valve combo
and Flow tested on 4.125 Flow Fixture , No Exhaust Flow Pipe
Meaux_Benoit_CED_Porting_Turbo292_Test#1_Sept_14_2021.jpg
Meaux_Benoit_CED_Porting_Turbo292_Test#2_Sept_15_2021.jpg
BenoitCED_IntBowl1.jpg
BenoitCED_ExhPort1.jpg
BenoitCED_Chamber1024x768.jpg
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Re: 292 Turbo Head Flow Tests

Post by steve cowan »

Larry,
Have you ever found dyno and or track performance between sharp angles under the valve seat and blended angles under the seat.
Appreciate the information on head dowels,I never even thought about that :D
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Re: 292 Turbo Head Flow Tests

Post by 1980RS »

Great work, looks like you make a Vortec like chamber for that head, I should do that to my 2 sets of Bowtie heads since you can't get anything for them these days.
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Re: 292 Turbo Head Flow Tests

Post by maxracesoftware »

1980RS wrote: Mon Jan 17, 2022 12:39 pm Great work, looks like you make a Vortec like chamber for that head, I should do that to my 2 sets of Bowtie heads since you can't get anything for them these days.

do you know which cast-iron #034 versions of Bowtie casting you have ??
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Re: 292 Turbo Head Flow Tests

Post by maxracesoftware »

steve cowan wrote: Mon Jan 17, 2022 5:25 am Larry,
Have you ever found dyno and or track performance between sharp angles under the valve seat and blended angles under the seat.
Appreciate the information on head dowels,I never even thought about that :D
on the "Cylinder Head Dowel-Pins Height and Holes" :
on some C/ED and B/ED cast-iron and aluminum SBC Heads
i've either used small Pioneer cast-iron tappered plugs,
or 0.050" offset steel Dowel-Pins ( or did both ), or Tig-welded aluminum Heads,
and relocated Dowel-Pin holes to further unshroud Intake Valves
@ 0.500" Valve Lift upwards , especially for 0.700" Lift Cams or greater .

especially on #292 or #034 cast-iron Heads , the Valves are moving
towards the Cylinder Bores at higher Valve Lifts , like if the Bore diameter
is 3.935 to 4.030 or even 4.060,
so that you can gain higher Lift Flow + Valve-to-Bore wall clearance
by moving the Cylinder upwards towards the Carb on both sides of the Block .

i've even offset-Bored Block's Cylinders for more clearance to run the largest
Intake i could get in a 3.935" Bore w/3.250 Stroke in the 1980's in C/ED 316CID
along with moving the Dowel-Pin holes in the Heads

i leave the Cylinder Head in place on the Vertical Mill
after i've scribed Lines all the way across the Heads deck surface
to locate the stock dowel-pin holes , set the X Y locations ,
then drill + plug holes , relocate holes , etc , light or heavy resurface afterwards .

same for aluminum Heads ...except i Tig the holes up while in place on the Vertical Mill
my 300 AMP Miller machine is just a few feet away from my Vertical Mill.

its a Win-Win , because as you start severly Angle-Milling Heads
either 0.000-0.150+ higher or an even greater "partial" Angle-Mill
like from just in front of 1st row of Headbolts towards spark plug end
0.000" there to 0.210+ ... you move the Intake Valve further away from the Cylinder Wall
and the other gain is you do not have to use double-thick Intake Gaskets
if you moved the Cyl Head upwards with relocating Dowel-Pin holes ,
that is , after you do such a severe Angle-Mill ,
you need to go back and correct/Mill the Intake gasket flanges back to 10deg Angle
or 10 1/8 deg Angle , and then it takes either 2 regular thin Intake gaskets
or combos of 2 extra Thick gaskets or 1 thin + 1 extra thick gasket
to make the Intake Manifold align back perfectly centered on Head Bolt intake holes .

if you look at the 1st #292 Turbo Head FlowSheet and Pics,
that Head was not Angle-Milled , and the 2 steam holes are not plugged up,
so that Cyl Head's Intake Valve with a 2.080" is much more shrouded at higher Valve Lifts
that the 2nd Head ( the C/ED #292 Head that is Angle-Milled )
so if i were to Angle-Mill the 1st Head as much as the 2nd Head ,
it would pickup Flow CFM , i also would need to rework Short Turn Curve back
after such an Angle-Mill amount ... and it would Flow better !

===========================================================

"Have you ever found dyno and or track performance between sharp angles under the valve seat
and blended angles under the seat."

Yes ... 3 very good Flowbench + Dyno + Dragstrip tests on BBC 632cid 1320 to 1380+ HP ranges
and relatively a 4th series likewise Tests, on SBC 407cid to 409cid 960 to 1005 HP 9400RPM tests,
and then again on some Chrysler 360cid NHRA SuperStock likewise Tests , 534HP to 561HP tests

Bill Jenkins 1st nailed-it in early 1970's with his SBC 331cid ProStock Book + #292 Turbo Heads

the Intake Seat with "very sharp" distinct multi-Angles
creates a type of "Self-Inducing Short Turn Flow Curve"
the sharp Angles make the Flow stay attached more ,
that is, you can chop away or lay back the entire Short Turn Curve ,
and to the Engine , it thinks you still have a nice looking radiused curve there !

the better Cyl Heads i've seen from like Tony Bischoff BES and Carl Foltz ,
have used or added a small 0.020" to 0.030" addition lower bottom cut transition,
this tiny bottom angle below the other normal bottom angle,
lets you lay back the entire Short Turn Curve without losing Flow CFM everywhere
in the Flow Lift Curve + it helps with increasing higher Valve Lift Flow CFM

on a BBC 632cid between 7600 to 8000 RPM point of Peak HP,
the very sharp Intake Seat Angles along with tiny additional lower bottom cut
makes highest HP Curve = 1380 to 1400 Peak HP @ 8000 RPM

without the tiny cut , its 1350 to 1360 Peak HP at 7800 to 7900 RPM

with same exact CNC'd Ports castings, Valves ,
its down to 1320 to 1330 Peak HP @ 7600 RPM with Intake Seat lower angles hand blended
into a radiused Curve instead of super sharp distinct Angles
it also loses 40 CFM on the FlowBench by 1.000+" Valve Lifts

with those same bad BBC Heads , i re-Valve Jobbed them back to very sharp bottom Angle
transitions as best i could, and got back HP to 1360's from 1330's before
could not really get them back all the way because there was not enough material
to shape .... and that was after i had to somewhat sink the Intake Valves
to get back enough material to create the sharp Angles back .

these larger BBC 632cid are great to experiment with or on ,
as typical Heads even BigChiefs have realtively very small Intake Valve sizes
even at 2.500" to 2.550" these Engine sizes are very starved for Flow
so that you can see effects of things you do easier .
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Re: 292 Turbo Head Flow Tests

Post by maxracesoftware »

more info :

i've even offset-Bored Block's Cylinders for more clearance to run the largest
Intake i could get in a 3.935" Bore w/3.250 Stroke in the 1980's in C/ED 316CID
along with moving the Dowel-Pin holes in the Heads

in 1980's , i found one of the "famous" 283cid Chevy II Blocks
for Steve Benoit's 316cid C/ED build up ( 3.935=Bore 3.250=Stroke 316cid C/ED = 1580+ Lbs )
... that particular Block had thicker Cylinder Walls and Deck Surfaces
and could easily spot it by its sculptured-reduced area around the Oil Filter
and somewhat a little different around the Clutch Bell Crank mounting threaded hole
in the Block , also , i've heard this particular Chevy II Block
was in Chevy Taxi Cab cars back then ??? i don't know if that was true ?

i took an aluminum plate and created a Clamp out of it,
that also mounted a Dial Indicator , that clamped around the Boring Bar's Column,
so that i could perfectly center the Bore Bar on the Cylinder
then shift it over according to Dial Indicator
and Offset Bore the Cylinder .. this helped unshroud the Intake Valve further,
so that you ended up with offset Bore + offset dowel-pin holes
and on 3.935" Bore + 2.035" Int Valve , it was definetly faster down the Dragstrip !

also, offset milling the Bores does slightly shift the Rod's small-end
on the Wrist pin , but theres still plenty side room for this to workout !

for Benoit's C/ED we got a great custom made Steel oil pan from
John Lingenfelter back in 1980's ... i still have that Oil Pan ,
i'll take a Pic and Post it , it was worth ET and MPH gains over what we first had .

so said that : Lingenfelter experimented with that Oil Pan and oil drain back time
to where He had just enough oil in the Pan thru the 1320 FT MPH clocks,
to keep maximum amount of oil off the crankshaft rotating assembly , ( reducing windage ) ,
as most of rest of the oil was in the Lifter galley , slowed down to return back to the Pan.

We just used the Pan like it was ,
and did not try to reduce any oil drainback time !
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Re: 292 Turbo Head Flow Tests

Post by FC-Pilot »

Larry, thanks for sharing this info so freely. It is great to stir some of our minds towards things in our own programs.

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Re: 292 Turbo Head Flow Tests

Post by 1980RS »

maxracesoftware wrote: Mon Jan 17, 2022 3:30 pm
1980RS wrote: Mon Jan 17, 2022 12:39 pm Great work, looks like you make a Vortec like chamber for that head, I should do that to my 2 sets of Bowtie heads since you can't get anything for them these days.

do you know which cast-iron #034 versions of Bowtie casting you have ??
I think one set is the early Phase 1 and the other set is the last set GM made that are the Phase 5 Bowtie heads. both set were crap out of the box like most GM heads were back in the day.
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Re: 292 Turbo Head Flow Tests

Post by rustbucket79 »

I love these old technology posts. =D>

I bought a set of phase 2 Bowties and invested untold hours into porting them with little more than Visard and Jenkins books and pictures to follow (this was in the early 90’s before any of this stuff was on the internet) and managed to get my 79 Camaro into the 10.70 range eventually with a roller 406 and these heads. I had 1 cylinder flowed, IIRC 262 intake, 224 exhaust.

Fast forward to last year and a job shows up with a pair of these heads, virgin, for a 400 build. Basics build, cut fresh seats and a minute blend into the runners. Feeling nostalgic I was hoping for good numbers, seems to me it was a struggle to reach 400. What a disappointment that was. Any aftermarket aluminum head will beat them out of the box.

I don’t miss those days hanging on a die grinder to be honest. 8)
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Re: 292 Turbo Head Flow Tests

Post by steve cowan »

As always Larry you are a true legend,excellent information.
I remember Darren Morgan mentioned that Carl foltz could maintain good high lift numbers with sharp angles,DM said it was difficult to do if I remember correctly. That extra cut you mention is that something you worked out early in your career??
At a guess I suspect that not all heads can only have one or the other bottom cuts and or blending due to application, short turn height/ shape and valve job height and angles used.
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Re: 292 Turbo Head Flow Tests

Post by maxracesoftware »

That extra cut you mention is that something you worked out early in your career??
no not me , i copied Foltz and BES , trying to create that same little ridge angle by Hand grinding,
not as good as BES and Foltz , but it was close enough to gain Flow and HP
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Re: 292 Turbo Head Flow Tests

Post by Walter R. Malik »

Here are some 1980 NASCAR flow numbers of cast iron Turbo 292 Chevy heads; no welding, brazing or epoxy.

Lift .... INT .... EXH (no pipe)
.200 .. 136.9 .. 108.4
.300 .. 195.2 .. 156.1
.400 .. 231.1 .. 185.0
.600 .. 265.6 .. 197.8
.700 .. 272.4 .. 198.3

2.020" & 1.600" valves

These are heads I actually used on my very low budget 366 Engine Masters Engine in 2002.
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Re: 292 Turbo Head Flow Tests

Post by maxracesoftware »

for Benoit's C/ED we got a great custom made Steel oil pan from
John Lingenfelter back in 1980's ... i still have that Oil Pan ,
i'll take a Pic and Post it , it was worth ET and MPH gains over what we first had .

so said that : Lingenfelter experimented with that Oil Pan and oil drain back time
to where He had just enough oil in the Pan thru the 1320 FT MPH clocks,
to keep maximum amount of oil off the crankshaft rotating assembly , ( reducing windage ) ,
as most of rest of the oil was in the Lifter galley , slowed down to return back to the Pan.

We just used the Pan like it was ,
and did not try to reduce any oil drainback time !
LingenfelterOilPan1.jpg
LingenfelterOilPan2.jpg
LingenfelterOilPan3.jpg
LingenfelterOilPan4.jpg
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Re: 292 Turbo Head Flow Tests

Post by maxracesoftware »

i took an aluminum plate and created a Clamp out of it,
that also mounted a Dial Indicator , that clamped around the Boring Bar's Column,
so that i could perfectly center the Bore Bar on the Cylinder
then shift it over according to Dial Indicator
and Offset Bore the Cylinder .. this helped unshroud the Intake Valve further,
so that you ended up with offset Bore + offset dowel-pin holes
and on 3.935" Bore + 2.035" Int Valve , it was definetly faster down the Dragstrip !

also, offset milling the Bores does slightly shift the Rod's small-end
on the Wrist pin , but theres still plenty side room for this to workout !
BoringBarClamp1.jpg
BoringBarClamp2.jpg
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