SBC various Vortec Dyno Tests and Flow Sheets

[maxracesoftware]

Larry
Are these all running a true HYD flat lifter?
Have you experimented with different preloads or are you your running them lashed?
Cheers James

all those Engines are running Rhoades Hydraulic Flat Tappet Lifters

Have you experimented with different preloads or are you your running them lashed?

Chris has on some of our Tests ... but i admit i'm typing down Info into WinDyn as Chris says the changes he makes
and sometimes in a hurry to do so ... some of the Info could be misunderstanding on the Hot Lash settings that are on the Dyno sheets ??

i'll ask/clarify Wednesday when we Dyno again

EDIT : i do a few Dyno tests with the Air Turbine to see if we are "Floating Valves "
Lashing Hydraulic Lifters tests shows up on the Air Turbine also

[MELWAY]

Thankyou Larry
Are you saying you have seen negative effects from running lash on Hyd flat lifters
We have some classes over here that mandate a HYD flat cam. And I’m not having much fun trying to rev them past 7500 and most lifters these days seem to bleed down excessively and be unreliable

[maxracesoftware]

Thankyou Larry
Are you saying you have seen negative effects from running lash on Hyd flat lifters
We have some classes over here that mandate a HYD flat cam. And I’m not having much fun trying to rev them past 7500 and most lifters these days seem to bleed down excessively and be unreliable

YES .... too much Valve Lash lost 25 HP top end
just enough = more HP

also we run a lot of Oil Pressure in these Engines

[GARY C]

Thankyou Larry
Are you saying you have seen negative effects from running lash on Hyd flat lifters
We have some classes over here that mandate a HYD flat cam. And I’m not having much fun trying to rev them past 7500 and most lifters these days seem to bleed down excessively and be unreliable

YES .... too much Valve Lash lost 25 HP top end
just enough = more HP

also we run a lot of Oil Pressure in these Engines

Are there rules against limiting travel or setting lifter at the bottom?

[MELWAY]

I guess you could limit travel
I have seen the consequence of too much pre load when they over rev them and float valve the lifter pumps up and valves crash into Pistons. So I’m trying to run zero pre load or some lash to. Avoid this

[PRH]

I’m curious about what the vacuum reading is measuring.
It’s quite a bit different on the stock heads after they’ve been reworked than the other tests.

I see this is a 2 year old thread...... apologies.

[maxracesoftware]

I’m curious about what the vacuum reading is measuring.
It’s quite a bit different on the stock heads after they’ve been reworked than the other tests.

I see this is a 2 year old thread...... apologies.

the difference in vacuum readings are :
for 1 engine its Plenum vacuum readings
and for the other engine its Vacuum Pump readings

[408 Nova]

In regard ..

The easiest way DV explains it is lc is linked to compression ratio. The higher the compression the smaller the chamber volume to scavenge. So the smaller the overlap triangle needs to be and the wider the lc. Thanks, Charlie

But 118 lsa is going quite a ways past the recommendations in DV formula for that aspect.. Not saying the results aren't real nice, just that its not totally explained by the compression ratio /lsa.. 118 lsa installed slightly retarded is so different from most recommendations you usually hear that it makes me wonder. Do you have any dyno numbers from the lower rpm range 3000-5000 ? Does it fall off real fast or drop unusually low anywhere in comparison the usual alternate cam choices?

I have used all the vortecs at one time or another. Currently EQ.. I have been running wider and wider lsa each time with decent results. Never beyond 113 lsa though. The vortecs "seemed" to like that more so than some other heads. Sorry no dyno #s , just curious.

i agree with the previous Post as it was stated,
but i do not agree 100% with DV LSA formula

Do you have any dyno numbers from the lower rpm range 3000-5000 ?
Does it fall off real fast or drop unusually low anywhere in comparison the usual alternate cam choices?

I have used all the vortecs at one time or another. Currently EQ..
I have been running wider and wider lsa each time with decent results.
Never beyond 113 lsa though. The vortecs "seemed" to like that more so than some other heads. Sorry no dyno #s , just curious.

these Dyno tests are the only time we made Dyno Pulls
befow 5000 RPM starting point :

He runs a 5000+ Stall Converter in the Mud Truck

we only started this Dyno Pull this low in RPM
because it had only 10.8:1 CR ( along with Q16 Gas )
so no chance of harming the engine at all


SBC Mud Truck
4.030x3.480=355.2 CID
ProMaxx Vortec Heads 2.055/1.600
Edelbrock Vortec Super Victor
Q16 Race Gas
10.8:1 CR
CompCams 5980/5985 118 251/247 .363/.363 118 Centers 116.5 CL
1.52 Roller Tip Steel Rockers
38 BTDC
LAT 20/50 Breakin Oil
Custom Kickout Oil Pan 10 Qts Oil


unmilled ProMaxx Heads
Peak TQ = 433.3 at 4800 RPM
Peak HP = 476.4 at 6500 RPM


So this is the smallest Cubic Inch Mud Truck engine we ever built/Dyno tested
i think it did really great for only 10.8:1 Compression Ratio , all things considered
476.4 Peak HP / 355.2 CID = 1.341216216 HP/CID Ratio


525.9 Peak HP = best Engine Combo at 361.5 CID
-476.4 Peak HP at 355.2 CID 10.8:1 CR
------------------
49.5 Peak HP difference


Compared to one of our best Engine Combos :
1.341216216 HP/CID Ratio x 361.5 cid = 484.8

so about 484.8 Peak HP if it were 361.5 CID engine size

then Angle-Mill the Heads 0.000-0.085" for almost 12.5:1 CR
12.5 - 10.8 = gain 1.7 points in Compression Ratio

then go from Q16 Race Gas to higher HP C45 Race Gas

then go from 1.52 Rocker Ratios to 1.72 Rocker Ratios

then lighter LAT Race Oil from LAT 20/50 Breakin Oil

and it should end up around 526 Peak HP

Note : CompCams 5980/5985 118 251/247 .363/.363 118 Centers 116.5 CL
Cam was on 116.5 IntCL and had 118.0=LSA
still made a lot of Torque

DV goes into the how's and why's of cam selection in his books, way beyond that formula he was messing with.

I know you're required to have 18" or so of vacuum for your mud truck small block, plus you've been doing this probably longer than I've been alive (I'm 48), so take this with a grain of salt because it's just for for the heck of it.

Let's take your 355 as an example.

One cylinder of 355.2 cubic inches total gives us 44.4 ci.

44.4/2.055 is 21.60. Rounding this to 22 and plugging this into his LCA chart in his book gives us a 107 LCA. This LCA works with your 10.8:1 compression and 1.52 rockers.

If you use smaller 2.02 intake valves, your LCA would need to be slightly tighter. If you used larger 2.10 intake valves, your LCA would need to be slightly wider.

If I put a 406 ci short block under those heads you're using with 2.055" valves, I would need to tighten the LCA.

If you bumped the compression from 10.8:1 to 12.8:1, the LCA required would need to be slightly wider. DV says .75 LCA wider for each ratio above 10.5:1.

Rocker ratio plays a role in it also. If your cam was optimized with 1.5 rockers, and then you swap to 1.7's, a wider LCA may be called for to restore overlap area back to where it was with the 1.5 rockers.


Comparing the valve events on our cams looks like this:

118/116.5 107/103
IO 9 BTDC IO 22.5 BTDC
IC 62 ABDC IC 48.5 ABDC
EO 63 BBDC EO 54.5 BBDC
EC 4 ATDC EC 12.5 ATDC

Overlap: 13 degrees 35 degrees

As you can see, the intake opens way earlier on the tighter LCA cam, meaning the intake valve is a lot higher off its seat as the piston starts down the bore, thus feeding that cylinder better, earlier on the intake stroke.

Post BDC filling of the cylinder on the intake stroke is not as great with the tighter LCA cam. There should be a good balance of opening and closing of the intake valve before and after the intake stroke, and the 107 LCA certainly looks like it's more balanced than the 118 LCA cam.

There is a lot more overlap with the tighter LCA cam, which will contribute to cylinder filling better before the intake stroke starts.

The exhaust valve on the wider LCA cam opens quite early, cutting into the power stroke more than the narrower LCA cam. This would decrease torque throughout the engine's rev range, with the 118 LCA cam probably only catching up torque wise right at the top of the engine's rev range.


I don't have a dyno, so I rely heavily on what DV has to say about cam selection. I've had very good results on the dragstrip using this cam selection technique. No one else I've seen has ever laid it out like DV to achieve cam selection like this.

Of course, there are more ways than one to skin a cat, and the way DV lays it out here is a way, and it's a very good way in my opinion.

[maxracesoftware]

In regard ..


But 118 lsa is going quite a ways past the recommendations in DV formula for that aspect.. Not saying the results aren't real nice, just that its not totally explained by the compression ratio /lsa.. 118 lsa installed slightly retarded is so different from most recommendations you usually hear that it makes me wonder. Do you have any dyno numbers from the lower rpm range 3000-5000 ? Does it fall off real fast or drop unusually low anywhere in comparison the usual alternate cam choices?

I have used all the vortecs at one time or another. Currently EQ.. I have been running wider and wider lsa each time with decent results. Never beyond 113 lsa though. The vortecs "seemed" to like that more so than some other heads. Sorry no dyno #s , just curious.

i agree with the previous Post as it was stated,
but i do not agree 100% with DV LSA formula

Do you have any dyno numbers from the lower rpm range 3000-5000 ?
Does it fall off real fast or drop unusually low anywhere in comparison the usual alternate cam choices?

I have used all the vortecs at one time or another. Currently EQ..
I have been running wider and wider lsa each time with decent results.
Never beyond 113 lsa though. The vortecs "seemed" to like that more so than some other heads. Sorry no dyno #s , just curious.

these Dyno tests are the only time we made Dyno Pulls
befow 5000 RPM starting point :

He runs a 5000+ Stall Converter in the Mud Truck

we only started this Dyno Pull this low in RPM
because it had only 10.8:1 CR ( along with Q16 Gas )
so no chance of harming the engine at all


SBC Mud Truck
4.030x3.480=355.2 CID
ProMaxx Vortec Heads 2.055/1.600
Edelbrock Vortec Super Victor
Q16 Race Gas
10.8:1 CR
CompCams 5980/5985 118 251/247 .363/.363 118 Centers 116.5 CL
1.52 Roller Tip Steel Rockers
38 BTDC
LAT 20/50 Breakin Oil
Custom Kickout Oil Pan 10 Qts Oil


unmilled ProMaxx Heads
Peak TQ = 433.3 at 4800 RPM
Peak HP = 476.4 at 6500 RPM


So this is the smallest Cubic Inch Mud Truck engine we ever built/Dyno tested
i think it did really great for only 10.8:1 Compression Ratio , all things considered
476.4 Peak HP / 355.2 CID = 1.341216216 HP/CID Ratio


525.9 Peak HP = best Engine Combo at 361.5 CID
-476.4 Peak HP at 355.2 CID 10.8:1 CR
------------------
49.5 Peak HP difference


Compared to one of our best Engine Combos :
1.341216216 HP/CID Ratio x 361.5 cid = 484.8

so about 484.8 Peak HP if it were 361.5 CID engine size

then Angle-Mill the Heads 0.000-0.085" for almost 12.5:1 CR
12.5 - 10.8 = gain 1.7 points in Compression Ratio

then go from Q16 Race Gas to higher HP C45 Race Gas

then go from 1.52 Rocker Ratios to 1.72 Rocker Ratios

then lighter LAT Race Oil from LAT 20/50 Breakin Oil

and it should end up around 526 Peak HP

Note : CompCams 5980/5985 118 251/247 .363/.363 118 Centers 116.5 CL
Cam was on 116.5 IntCL and had 118.0=LSA
still made a lot of Torque

DV goes into the how's and why's of cam selection in his books, way beyond that formula he was messing with.

I know you're required to have 18" or so of vacuum for your mud truck small block, plus you've been doing this probably longer than I've been alive (I'm 48), so take this with a grain of salt because it's just for for the heck of it.

Let's take your 355 as an example.

One cylinder of 355.2 cubic inches total gives us 44.4 ci.

44.4/2.055 is 21.60. Rounding this to 22 and plugging this into his LCA chart in his book gives us a 107 LCA. This LCA works with your 10.8:1 compression and 1.52 rockers.

If you use smaller 2.02 intake valves, your LCA would need to be slightly tighter. If you used larger 2.10 intake valves, your LCA would need to be slightly wider.

If I put a 406 ci short block under those heads you're using with 2.055" valves, I would need to tighten the LCA.

If you bumped the compression from 10.8:1 to 12.8:1, the LCA required would need to be slightly wider. DV says .75 LCA wider for each ratio above 10.5:1.

Rocker ratio plays a role in it also. If your cam was optimized with 1.5 rockers, and then you swap to 1.7's, a wider LCA may be called for to restore overlap area back to where it was with the 1.5 rockers.


Comparing the valve events on our cams looks like this:

118/116.5 107/103
IO 9 BTDC IO 22.5 BTDC
IC 62 ABDC IC 48.5 ABDC
EO 63 BBDC EO 54.5 BBDC
EC 4 ATDC EC 12.5 ATDC

Overlap: 13 degrees 35 degrees

As you can see, the intake opens way earlier on the tighter LCA cam, meaning the intake valve is a lot higher off its seat as the piston starts down the bore, thus feeding that cylinder better, earlier on the intake stroke.

Post BDC filling of the cylinder on the intake stroke is not as great with the tighter LCA cam. There should be a good balance of opening and closing of the intake valve before and after the intake stroke, and the 107 LCA certainly looks like it's more balanced than the 118 LCA cam.

There is a lot more overlap with the tighter LCA cam, which will contribute to cylinder filling better before the intake stroke starts.

The exhaust valve on the wider LCA cam opens quite early, cutting into the power stroke more than the narrower LCA cam. This would decrease torque throughout the engine's rev range, with the 118 LCA cam probably only catching up torque wise right at the top of the engine's rev range.


I don't have a dyno, so I rely heavily on what DV has to say about cam selection. I've had very good results on the dragstrip using this cam selection technique. No one else I've seen has ever laid it out like DV to achieve cam selection like this.

Of course, there are more ways than one to skin a cat, and the way DV lays it out here is a way, and it's a very good way in my opinion.

Good info as always Larry! Although you should probably read some of the recent threads and realize a 2.055 intake valve and 1.875" header won't work in a OEM Vortec head
Pete Graves
CPMotorworks,Inc.
Custom Engine Machining
Cylinder Head Fixture for Vertical / Surfacing Mills

" Although you should probably read some of the recent threads and realize a 2.055 intake valve and 1.875" header won't work in a OEM Vortec head "

i love that Quote by Pete !!

i've tested a 2.080" intake valve in #062 castings 3 different engines
1= local Racer ... engine picked up TQ and HP from 2.055/1.600 combo in #062 castings
2= was Harry Clack's ( Lafayette.LA) Sweden DragRace Boat 377cid with 2.080" int valves , came very close to breaking that MPH Record
made more TQ and HP on my Dyno
3= another local Racer #062 castings 2.080/1.600 ... but these lost a few HP from 2.055/1.600 combo
on these #062 castings , they had a lot of core-shift , so i could not maxout the Intake Bowl Short Turn Curve without breaking into water jacket !

so from that point on , i never again attempted to install 2.080" intake valves , just only 2.055/1.600 combo

Cyl Head Core-Shift problems :
original ProAction 14deg cast-iron Heads
1st pair , no bad core-shift , was able to maxout short turn curves
2nd pair, real bad core-shift , one end of Head had combustion chamber really thick wall around exhaust valve,
the other side of Head the chamber was only 0.080" thick in corner around exhaust valve , it eventually cracked there and had to have it welded-up .

same thing with end-cylinder still had 0.200" thick walls after i maxed out the Short Turn Curves
the other end of that same Head , i could not maxout that Intake Short Turn Curve, so that Intake Port ended up not Flowing that well
so Craig A/ND Heads ended up with basically 2 cylinders on each Head that were great, and other 2 cylinders that weren't
so on a V8 it was like 4 great cylinders and 4 other not so great cylinders
still managed to make 960's HP on then was a 403cid engine @ 9300 to 9400 RPM


in PipeMax v4.50 it has a choice : " Plenum Vacuum Rule • MotorSports Classes"
so it will predict Cam Specs for those applications

but if you just use the Default choice : " Race Engine • Mid-Range Peak TQ • Hi RPM Peak HP"
or choose the type : " Hi-Perf Engine • Low-to-Mid-Range RPM Torque + HP"
it will probably come very close to predicting Cam Specs David Vizard 's LSA

one of included example file in the PipeMax v4.50 installation is :
350_Vortec_Vizards_Sledgehammer_6200RPM_447HP__4400RPM_445TQ__355cid.PMW

Application Type : " Hi-Perf Engine • Low-to-Mid-Range RPM Torque + HP"

the Vizard File almost exact match to Cam Specs he used in that Engine !

Code: Select all

Bore=4.03000   Stroke=3.48000   355.11515321 Cubic Inches @ 6200 RPM  Intake System= 101.63413 VE%
Complete Intake System Flow     @28in.= 195.9021 -to- 209.7833 CFM @ 0.563200 Lift (17.69000 VE% Loss)
Cylinder Head  Intake Port Flow @28in.= 230.0000 -to- 246.2973 CFM @ 0.563200 Lift (119.32413 VE%)
Cylinder Head Exhaust Port Flow @28in.= 165.5000 -to- 177.2270 CFM @ 0.563200 Lift (no Flow Pipe)

Dyno HP Weather Correction Equation = 8•  SAE J607 (June1974) • STP • SuperFlow-FTQ • (Default)
Air Correction=0.90768188  Station Barometer=29.48000000  Air DegF=96.00  Vapor Pressure=0.442
HP Correction Factor= 1.083533596     Fuel Type= Gasoline  •  Pump Gas  •  ( 91 to 93 Octane Premium )
Fuel BTU=19000.0  Air/Fuel Ratio=12.532835  BSFC=0.520393  Mixture Distribution= 90.0 Quality= 90.0
Step Oil Pan  •  Regular Oil  •  0.0 inHg • 0.0 kPa Vacuum • Harmonic Damper Efficiency= 90.0 %
Engine Application  =   Hi-Perf Engine • Low-to-Mid-Range RPM Torque and HP
-----------------------------------------------------------------------------------------------------
                                  Camshaft = Hydraulic  Roller  Lifter
300 RPM/Sec Dyno Test             Level=4        Level=5        Level=6        Level=7    Piston FPM
Peak HorsePower    @  6200 RPM      430.4          435.9          441.4          447.0      3596.00
Peak Torque Lbs-Ft @  4400 RPM      416.3          421.6          426.9          432.3      2552.00

HorsePower per CID                  1.212          1.227          1.243          1.259   Peak HP Fuel
Torque per Cubic Inch               1.172          1.187          1.202          1.217   consumed in
Peak Torque BMEP in psi             176.8          179.0          181.3          183.6   Lbs./ Hour
Throttle Plate CFM @ 1.5 inHg.        760            846            888            931      214.7
--------------------------------- Recommended Camshaft Specs at 0.050” inch Lobe Lift ---------------
Cam Lobe Separation Angle (LSA)   107.173        107.173        107.173        107.173
Intake  Minimum Valve Lift        0.48947        0.50965        0.53067        0.55255
Exhaust Minimum Valve Lift        0.47621        0.49585        0.51629        0.53758
Intake  Minimum Duration          217.757        219.292        220.838        222.395
Exhaust Minimum Duration          218.161        219.699        221.247        222.807
Overlap Minimum Duration            3.613          5.150          6.697          8.255

Intake  Maximum Valve Lift        0.50965        0.53067        0.55255        0.57533
Exhaust Maximum Valve Lift        0.49585        0.51629        0.53758        0.55975
Intake  Maximum Duration          219.292        220.838        222.395        223.963
Exhaust Maximum Duration          219.699        221.247        222.807        224.378
Overlap Maximum Duration            5.150          6.697          8.255          9.824
-----------------------------------------------------------------------------------------------------
* above Specs adjusted for ValveTrain Deflection= 0.0000   Intake Lash= 0.0000   Exhaust Lash= 0.0000
* User's current Camshaft Specs :              OverLap Duration =   8.00000
Lobe Separation Angle (LSA)= 108.00000         Camshaft Advanced = 4.00000 degrees     
Intake Lobe CenterLine = 104.00000             Exhaust Lobe CenterLine = 112.00000
Intake Duration = 224.00000 @ 0.05000”         Exhaust Duration = 224.00000 @ 0.05000”
Intake Open =   8.00000 BTDC                   Exhaust Open =  44.00000 BBDC
Intake Close=  36.00000 ABDC                   Exhaust Close=   0.00000 TDC
Intake Rocker Ratio = 1.60000:1                Exhaust Rocker Ratio = 1.60000:1
Intake Lobe Lift = 0.352000                    Exhaust Lobe Lift = 0.352000
Intake Valve Lift = 0.563200                   Exhaust Valve Lift = 0.563200
-----------------------------------------------------------------------------------------------------
Intake Pumping Choke Valve Lift= 0.612163      Exhaust Pumping Choke Valve Lift= 0.602085
Intake Time Area TQ Valve Lift = 0.718969      Exhaust Time Area TQ Valve Lift = 0.704015
Intake Time Area HP Valve Lift = 0.821423      Exhaust Time Area HP Valve Lift = 0.787587
Intake System Flow Valve Lift  = 0.631459      Exhaust System Flow Valve Lift  = 0.640686
Intake Port Flow Valve Lift    = 0.667920      Exhaust Port Flow Valve Lift    = 0.621592
Intake Curtain Flow Valve Lift = 0.705231      Exhaust Curtain Flow Valve Lift = 0.661756
Intake Z-Factor Valve Lift     = 0.668607      Exhaust Z-Factor Valve Lift     = 0.622630

0.250 L/D Ratio Int Valve Lift = 0.485000      0.250 L/D Ratio Exh Valve Lift  = 0.375000
Note : the Valve Curtain Area will equal the Valve Area @ 0.250 Valve Lift/Diameter Ratio
Intake Mach Z-Factor     =  52.7573 % SOS      Exhaust Mach Z-Factor = 68.2328 % SOS
Mach Z-Factor definition = PerCent % of the Speed of Sound ( SOS ) at the Valve's Curtain Area
Mach Z-Factor Valve Lift = Level=10 Cam calculated Speed of Sound velocity thru Valve Curtain Areas
Pumping Choke Valve Lift = Level=10 Cam calculated Intake and Exhaust Valve Diameters and RPM Range
Time Area Valve Lifts    = Level=10 Cam calculated User's Camshaft Durations, Curtain Areas, RPM Range
System Flow Valve Lift   = Level=10 Cam calculated Intake and Exhaust System Flow and Valve Diameters
Port Flow Valve Lift     = Level=10 Cam calculated Intake and Exhaust Port's Flow and Valve Diameters
Curtain Flow Valve Lifts = Level=10 Cam calculated Flow thru Intake and Exhaust Valve Curtain Areas

DCR Cylinder Volume CC   =  677.286370         Dynamic Compression Ratio     = 9.379816:1
DCR Effective Stroke     =  3.2402 inches      Valve Lash Compression Ratio  = 7.987053:1
Static Compression Ratio =  10.000000:1        Ve% + Lash Compression Ratio  = 9.530482:1
Cranking Psi @ 150 RPM = 164.2 Psi -to- 187.7 Psi @ 260 RPM (depending on Ring seal + Piston Rock)

Station Barometer NOAA= 29.48885898   Pressure Altitude Feet= 410.5   Z•Elevation Feet= 0.0
Density Altitude Feet = 3025.3    Relative Humidity % = 25.81    Dew Point DegF = 55.40
Virtual Temperature DegF = 99.17    Water Grains = 66.27        Wet Bulb DegF = 69.84

Bore=4.03000   Stroke=3.48000   355.11515321 Cubic Inches @ 6200 RPM  Intake System= 101.63413 VE%
Complete Intake System Flow     @28in.= 195.9021 -to- 209.7833 CFM @ 0.563200 Lift (17.69000 VE% Loss)
Cylinder Head  Intake Port Flow @28in.= 230.0000 -to- 246.2973 CFM @ 0.563200 Lift (119.32413 VE%)
Cylinder Head Exhaust Port Flow @28in.= 165.5000 -to- 177.2270 CFM @ 0.563200 Lift (no Flow Pipe)

Dyno HP Weather Correction Equation = 8•  SAE J607 (June1974) • STP • SuperFlow-FTQ • (Default)
Dyno Air Correction=0.90768188   Fuel Type= Gasoline  •  Pump Gas  •  ( 91 to 93 Octane Premium )
Station Barometer=29.48000000  Air DegF=96.00  Vapor Pressure=0.442  Density Altitude Feet=3025.3
Pressure Altitude Feet= 410.5    Relative Humidity % = 25.81    Dew Point DegF = 55.40
Virtual Temperature DegF = 99.17    Water Grains = 66.27        Wet Bulb DegF = 69.84
Step Oil Pan  •  Regular Oil  •  0.0 inHg • 0.0 kPa Vacuum • Harmonic Damper Efficiency= 90.0 %
Engine Application  =   Hi-Perf Engine • Low-to-Mid-Range RPM Torque and HP

       FlowVe%	Plenum	Front	Rear	Total	 BTU	Intake	UnCorr	Engine	Piston	Frequency
Engine	101.634	Vacuum	Fuel	Fuel	Fuel	 Heat	Flow	Peak	HP/CID	Speed	per second
RPM	SCFM	In.Hg.	Lbs/Hr	Lbs/Hr	Lbs/Hr	 HP	 CFM	 HP	Ratio	 FPM	Hertz
6200	587.7	1.042	107.3	107.3	214.7	1602.7	195.9	412.5	1.162	3596.0	51.7
-------------------------------------------------------------------------------------------------------
                                  Camshaft = Hydraulic  Roller  Lifter
300 RPM/Sec Dyno Test             Level=4        Level=5        Level=6        Level=7
Peak HorsePower    @  6200 RPM      430.4          435.9          441.4          447.0  Peak HP CBHP
Brake Specific Fuel Consumption    0.5404         0.5337         0.5270         0.5204  BSFC Lbs/HP-hour
Brake Specific  Air Consumption    6.7728         6.6882         6.6046         6.5220  BSAC Lbs/HP-hour
Brake Thermal Efficiency PerCent   24.786         25.100         25.418         25.740  BTE percent %
Brake Mean Effective Pressure       154.8          156.8          158.8          160.8  BMEP Psi
Peak Horsepower per Cubic Inch      1.212          1.227          1.243          1.259  HP/CID Ratio
Throttle Plate CFM @ 1.5 inHg.        760            846            888            931  CFM @ 1.5 inHg
-------------------------------------------------------------------------------------------------------
Peak Torque Lbs-Ft @  4400 RPM      416.3          421.6          426.9          432.3  Peak TQ CBTQ
Brake Specific Fuel Consumption    0.4733         0.4674         0.4616         0.4558  BSFC Lbs/HP-hour
Brake Specific  Air Consumption    5.9323         5.8581         5.7849         5.7126  BSAC Lbs/HP-hour
Brake Thermal Efficiency PerCent   28.298         28.657         29.019         29.387  BTE percent %
Brake Mean Effective Pressure       176.8          179.0          181.3          183.6  BMEP Psi
Peak Torque per Cubic Inch          1.172          1.187          1.202          1.217  TQ/CID Ratio
-------------------------------------------------------------------------------------------------------

[Erland Cox]

Larry, out of curiosity.
If there was no vacuum rule and you built the engines the same except timing, how would you change the camshaft?
And how would that change the output?

Erland

[maxracesoftware]

Larry, out of curiosity.
If there was no vacuum rule and you built the engines the same except timing, how would you change the camshaft?
And how would that change the output?

Erland

you mean keep the Hydraulic Cam minus the Rhoades Lifters ?
if so ... it would be between 110 to 112 LSA and 244/248 Durations @ 0.050" with 0.620"/.0620" Valve Lifts
that would make more Peak TQ and maybe more Peak HP
it shouldn't end up less than before ??

" Although you should probably read some of the recent threads and realize a 2.055 intake valve and 1.875" header won't work in a OEM Vortec head "
i love that Quote by Pete !!

Erland ... you ever seen this kind of Drag Race Boat ... its from Sweden ... we almost got the MPH Record with 2.080/1.600 Vortec Heads
it was a 372cid or 377cid , more likely 372cid SBC ... memory sucks ! ... i just noticed its a 377cid
ATC = Advanced Transmissions - Lafayette , LA

[Erland Cox]

That is a lot of lift with that short duration.
How do you make a flat tappet cam live with that acceleration?
What open and closed pressures would that lift and duration need?
No problems with loss of lift with hydraulic lifters?

Erland

[1980RS]

Boy, after reading all the good stuff about the Vortec heads in this thread, I feel like I didn't make any power this year with my set of Vortecs having only 1.94 and 1.5 valves.

This is a great and interesting thread by the way. 3 thumbs up on this kind of head work by all you guys.