[pastry_chef]

Originally Posted by slowbird

Why were my heads better

Area under the flow curve and well matched to that displacement / RPM.

Yes, the other wideport dyno'd.

Once you lift the valve off the seat, duration at other points are set by fill efficiency, think velocity / pressure differential.

[Scott Stoneburg]

Dur. advertised 308-312. @ 050 276- 280. lobes 441 in. Ex 441 lobe
LOBE SEP 110 - Install 106..
This is what Bullet spec'd for my 461. Never tried it because it was so close to the cam I was running. Expected to make power by 6500-6800

[slowbird]

Originally Posted by pastry_chef

Your 496 ran a much better head/intake. And peaked exactly where my math says it would.

Another Brian more than 10 years ago ran a 11:1 461 - Butler E-wideport with Victor, 272 / 280 @ .050 and it peaked at 6900 RPM. Less lift . 440 lobe.

Originally Posted by pastry_chef

Area under the flow curve and well matched to that displacement / RPM.

Yes, the other wideport dyno'd.

Once you lift the valve off the seat, duration at other points are set by fill efficiency, think velocity / pressure differential.

So if 2 heads have same csa but one flows 30cfm more, it will have a high rpm peak? I kind of thought csa set rpm and flow was hp potential?

[Bill Eveland]

For 6700 i was speced out 268/275 @.050. .465 lobe 110 lsa . For more rpm 275/281. .465, .455 lobe 110 lsa

[PAUL K]

Originally Posted by Scott Stoneburg

Dur. advertised 308-312. @ 050 276- 280. lobes 441 in. Ex 441 lobe
LOBE SEP 110 - Install 106..
This is what Bullet spec'd for my 461. Never tried it because it was so close to the cam I was running. Expected to make power by 6500-6800

The 276/280 would make power to 6500/6800?

[PAUL K]

Originally Posted by Bill Eveland

For 6700 i was speced out 268/275 @.050. .465 lobe 110 lsa . For more rpm 275/281. .465, .455 lobe 110 lsa

The first cam is a good choice for your latest combination but I'd back off on the lobe lift some using a factory block.

[slowbird]

Originally Posted by PAUL K

The first cam is a good choice for your latest combination but I'd back off on the lobe lift some using a factory block.

Also id go to a 108ls but that's just my opinion

[pastry_chef]

Originally Posted by slowbird

I kind of thought csa set rpm and flow was hp potential?

Somewhat agree but many other things factor as well.
In recent times I try and look more into velocity and mass flow.
Some have also said peak HP happens where the engine cannot fully purge exhaust gas.

[slowbird]

Also Darby's stock block peaked at 6500 with 265@.050 and kre d-ports. I would hope/think wide ports would push that higher and then higher yet with more duration

[Scott Stoneburg]

Originally Posted by PAUL K

The 276/280 would make power to 6500/6800?

Thats what i was informed. Like I say i never tried it. My cam was 268/276 @ .050 with a .403 lobe. It made power to 6200-6500 I shifted at 6500. It didnt make crazy power, 550HP to the rear tires and went 10.20@ 131 in my 3500 lb street car.

[slowbird]

Originally Posted by Scott Stoneburg

Thats what i was informed. Like I say i never tried it. My cam was 268/276 @ .050 with a .403 lobe. It made power to 6200-6500 I shifted at 6500. It didnt make crazy power, 550HP to the rear tires and went 10.20@ 131 in my 3500 lb street car.

What heads and intake?

[Stan Weiss]

While Mike / Pasty_Chef did help me with testing this is still not a Production program. So feedback is welcome.

Stan


T M C -- David Vizard's -- Torque Master Cams
Pontiac Solid Roller Lifter Cam and Engine Component Selector

Bore = 4.155
Stroke = 4.25
Cubic Inches = 461
Rod Center to Center Length = 6.7
Intake Valve Diameter = 2.2
Exhaust Valve Diameter = 1.77
Compression Ratio = 11.0
Peak Power RPM = 7300
Peak HP Piston Speed = 5171
LCA = 111
0.020 Duration Intake = 293
0.020 Duration Exhaust = 297
Overlap @ 0.020 = 73.0
Advance = 4.3
Intake Centerline = 106.7
Recommended Minimum Intake Valve Lift = 0.786
Recommended Minimum Exhaust Valve Lift = 0.754
Vacuum at Idle = 9.0
Dynamic Compression Ratio = 7.7
Cranking Cylinder Pressure - PSI = 195
Estimated Torque Potential Lbs-Ft = 626
Estimated Power Potential HP = 770
Required Minimum CFM Head Port Flow = 364
Target Intake Port cc's = 254

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

T M C -- David Vizard's -- Torque Master Cams
Pontiac Hydraulic Roller Lifter Cam and Engine Component Selector

Bore = 4.155
Stroke = 4.25
Cubic Inches = 461
Rod Center to Center Length = 6.7
Intake Valve Diameter = 2.2
Exhaust Valve Diameter = 1.77
Compression Ratio = 11.0
Peak Power RPM = 6850
Peak HP Piston Speed = 4852
LCA = 109
0.006 Duration Intake = 304
0.006 Duration Exhaust = 308
Overlap @ 0.006 = 88.0
Advance = 4.3
Intake Centerline = 104.7
Recommended Minimum Intake Valve Lift = 0.765
Recommended Minimum Exhaust Valve Lift = 0.742
Vacuum at Idle = 9.2
Dynamic Compression Ratio = 7.9
Cranking Cylinder Pressure - PSI = 202
Estimated Torque Potential Lbs-Ft = 655
Estimated Power Potential HP = 763
Required Minimum CFM Head Port Flow = 365
Target Intake Port cc's = 254

[Jay S]

Just my opinion. A wide port engine is going to want to run a tighter lsa than a high port. I tend to agree 110 might be a little wide. I would probably look at a 106-108 LSA rather than 110 on those cams that have been discussed. Even if heads appear to flow identical, the wide port is more than likely going to loose some air velocity against a cathedral or high port, especially if both ports are feeding the same valve size. Increasing the scavenging would probably help overcome that some. Coriolis effect on a high port versus a wide port is likely swapping some port volume for velocity to get the same air flow on wider ports.

[slowbird]

Originally Posted by Stan Weiss

While Mike / Pasty_Chef did help me with testing this is still not a Production program. So feedback is welcome.

Stan


T M C -- David Vizard's -- Torque Master Cams
Pontiac Solid Roller Lifter Cam and Engine Component Selector

Bore = 4.155
Stroke = 4.25
Cubic Inches = 461
Rod Center to Center Length = 6.7
Intake Valve Diameter = 2.2
Exhaust Valve Diameter = 1.77
Compression Ratio = 11.0
Peak Power RPM = 7300
Peak HP Piston Speed = 5171
LCA = 111
0.020 Duration Intake = 293
0.020 Duration Exhaust = 297
Overlap @ 0.020 = 73.0
Advance = 4.3
Intake Centerline = 106.7
Recommended Minimum Intake Valve Lift = 0.786
Recommended Minimum Exhaust Valve Lift = 0.754
Vacuum at Idle = 9.0
Dynamic Compression Ratio = 7.7
Cranking Cylinder Pressure - PSI = 195
Estimated Torque Potential Lbs-Ft = 626
Estimated Power Potential HP = 770
Required Minimum CFM Head Port Flow = 364
Target Intake Port cc's = 254

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

T M C -- David Vizard's -- Torque Master Cams
Pontiac Hydraulic Roller Lifter Cam and Engine Component Selector

Bore = 4.155
Stroke = 4.25
Cubic Inches = 461
Rod Center to Center Length = 6.7
Intake Valve Diameter = 2.2
Exhaust Valve Diameter = 1.77
Compression Ratio = 11.0
Peak Power RPM = 6850
Peak HP Piston Speed = 4852
LCA = 109
0.006 Duration Intake = 304
0.006 Duration Exhaust = 308
Overlap @ 0.006 = 88.0
Advance = 4.3
Intake Centerline = 104.7
Recommended Minimum Intake Valve Lift = 0.765
Recommended Minimum Exhaust Valve Lift = 0.742
Vacuum at Idle = 9.2
Dynamic Compression Ratio = 7.9
Cranking Cylinder Pressure - PSI = 202
Estimated Torque Potential Lbs-Ft = 655
Estimated Power Potential HP = 763
Required Minimum CFM Head Port Flow = 365
Target Intake Port cc's = 254

Very interesting Stan. So what changes if heads have 2.25in 1.74ex and 300cc runner?
Why not have both the cams listed as either solid or hyd?

[Dragncar]

Originally Posted by slowbird

Just for fun/discussion, how would you guys cam a 11:1 pump gas street/strip 461ci with edelbrock wide port heads that flow 360-370cfm. I have my ideas just wondering what others think and why you think it.
And last but not least, would it be a dog no matter the cam used?

There are some LS engines with less than 461 ci which have heads that flow that much, puny cams. And they are no dogs, very efficient.

Your engine, do you have a flow sheet for the heads you are using you can post. How can you ask people to cam it if you are just giving out max cfm ? If it takes .900 lift to get your 370cfm who cares, means nothing.
Need to have the complete flow sheet to find out where it falls off. Where its done at. Keep it in its happy place then shift.

[Scott Stoneburg]

Originally Posted by slowbird

What heads and intake?

Edelbroke heads. Not wide ports, but they did require offset rockers. Flow was atound 345 @ .700 with a Victor manifold. I wasnt taking full advantage of the heads with the cam. I had 1.55 shaft rockers so the lift was .620 before lash.

[slowbird]

Originally Posted by Dragncar

There are some LS engines with less than 461 ci which have heads that flow that much, puny cams. And they are no dogs, very efficient.

Your engine, do you have a flow sheet for the heads you are using you can post. How can you ask people to cam it if you are just giving out max cfm ? If it takes .900 lift to get your 370cfm who cares, means nothing.
Need to have the complete flow sheet to find out where it falls off. Where its done at. Keep it in its happy place then shift.

Lol no need for flow sheet, this is just for run as title says. Plus no one else has asked for one. And ive never used cfm to cam an engine before and think i've done pretty well.

[PontiacJim1959]

He is what I am thinking, the theoretical numbers being thrown out are seemingly for a max RPM/power number build.

Being a street engine, shooting for the above, what kind of street manners would a cam like that have? The huge ports/CFM's would essentially mean a lazy port velocity at lower RPM's. I think it would be miserable, but no doubt some do do this and say they have no issues on the street. (?) I think 280-290 CFM for a street build would be far better and more responsive on the street.

Wouldn't you also need gearing/high stall converter to keep RPM's up just to drive it comfortably on the street? So I think this theoretical build would be more on the side of a race engine rather than a street engine unless street racing was in mind. I don't think I would be driving it much on the street with the gas mileage an engine like this won't get.

[i82much]

The only cams allowed for discussion in the street section are the 041 and Old Faithful. Moderator - please lock this thread.

[Stan Weiss]

Originally Posted by slowbird

Very interesting Stan. So what changes if heads have 2.25in 1.74ex and 300cc runner?
Why not have both the cams listed as either solid or hyd?

Brian,
This is not an engine simulation package so things look cfm and port volume are calculated outputs. I will look at the calculation for port volume as the calculated volume is a little low. The listed duration for a solid and hyd are at different lifter raise.

Stan

This is with the different valve sizes.

T M C -- David Vizard's -- Torque Master Cams
Pontiac Hydraulic Roller Lifter Cam and Engine Component Selector

Bore = 4.155
Stroke = 4.25
Cubic Inches = 461
Rod Center to Center Length = 6.7
Intake Valve Diameter = 2.25
Exhaust Valve Diameter = 1.74
Compression Ratio = 11.0
Peak Power RPM = 6750
Peak HP Piston Speed = 4781
Intake Rocker Arm Ratio = 1.65
Exhaust Rocker Arm Ratio = 1.65
Single or Dual Pattern = 1
LCA = 109
0.006 Duration Intake = 296
0.006 Duration Exhaust = 300
Overlap @ 0.006 = 80.0
Advance = 3.5
Intake Centerline = 105.5
Recommended Minimum Intake Valve Lift = 0.765
Recommended Minimum Exhaust Valve Lift = 0.742
Vacuum at Idle = 11.3
Dynamic Compression Ratio = 8.2
Cranking Cylinder Pressure - PSI = 211
Estimated Torque Potential Lbs-Ft = 663
Estimated Power Potential HP = 763
Required Minimum CFM Head Port Flow = 365
Target Intake Port cc's = 254