[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?

[Steve C.]

Can we not presume one deciding factor could or would be at what rpm would you want the combination to make peak power at ?

Also I will presume on such a head that cfm flow is probably rated at 0.700" lift or higher. Many would suggest the cam should be designed for maximum lift to take advantage of that.


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[slowbird]

Originally Posted by Steve C.

Can we not presume one deciding factor could or would be at what rpm would you want the combination to make peak power at ?


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6800rpm sound good?

[pastry_chef]

I'd prefer KRE high ports over E wide ports.

For this example we don't know CSA, throat size but I'd guess a bit higher than 6800 RPM. Maybe 7200 RPM or so.

[slowbird]

Originally Posted by pastry_chef

I'd prefer KRE high ports over E wide ports.

For this example we don't know CSA, throat size but I'd guess a bit higher than 6800 RPM. Maybe 7200 RPM or so.

What cam and why.
A Butler wide port has a mcsa of around 3.35-3.4

[Steve C.]

To further muddy the water, what Combustion chamber design ? The old style or the revised CNC design that will allow more compression and can influence the cam design.


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[slowbird]

Originally Posted by Steve C.

To further muddy the water, what Combustion chamber design ? The old style or the revised CNC design that will allow more compression and can influence the cam design.


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I set compression at 11:1 in first post.
You really think there is that big of difference in the two designs? Maybe there is??

[Steve C.]

Since this is in the street section I'm presuming the use of pump gas in this conversation. The chamber design has some affect on the situation if you want to push the envelope. To some 11:1 would be doing so.

( Side note, and only to serve as an example. Regarding Edelbrock heads and the older design chamber you can run more compression with the 72cc chamber vs the 87cc chamber because of the slight difference in design. But here that's a moot point because the obvious these heads would not start out with 87cc castings )


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[pastry_chef]

A starting intake lobe would probably be something like:

Comp HXL
2233 303 274 197 .454
2234 305 276 199 .454

1.7 or 1.75 rocker if I could.

[slowbird]

Originally Posted by pastry_chef

A starting intake lobe would probably be something like:

Comp HXL
2233 303 274 197 .454
2234 305 276 199 .454

1.7 or 1.75 rocker if I could.

That's a pretty good sized lobe for a 11:1 461 street/race engine

[JLMounce]

This engine sounds pretty similar in build to an LSX 454. It’s not an apple to apple comparison of course with the lsx head flowing around 370cfm at .700 and having a more efficient port. That said, I believe that engine runs a cam in the 236/247 range with 1.8 ratio rockets. Lift is close around .65 with a 1.8 rocker.

I’d think something in the 240/250 range might be a good place to start looking.

[Steve C.]

Stated .... "That's a pretty good sized lobe for a 11:1 461 street/race engine

Yes, but your tossing out wicked peak power RPM numbers for a 'street car' !

I ran a UltraDyne sold roller with 279/287 at .050 with a 110 lobe separation.
It made peak power at 6900/7000 rpm on the dyno. 'Bigger' than the cam pastry_chef mentions. BUT not apples-to-apples, my engine had a shorter 4.125 stroke. Also, and important, the Edelbrock heads had a much smaller 236cc intake runner volume.

( TH400 transmission with manual valve body and a 8-inch Hughes Performance converter. 3.73 to 4.30 gears. 28" tires and a 4675 lb race weight. The Edelbrock heads had 11.2 compression with the older design chamber. At the track we ran 105-octane race gas. It was limited street driven but I had to add race gas in with 93 octane pump gas. 10.36 at 129 mph on the motor and 9.59 at 140 mph with a single nitrous plate )


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[pastry_chef]

Originally Posted by slowbird

That's a pretty good sized lobe for a 11:1 461 street/race engine

Yes.
Well aligned to the oversize head.

[pastry_chef]

Originally Posted by JLMounce

LSX 454. It’s not an apple to apple comparison of course with the lsx head flowing around 370cfm at .700 and having a more efficient port. That said, I believe that engine runs a cam in the 236/247 range with 1.8 ratio rockets. Lift is close around .65 with a 1.8 rocker.

LSX454 makes peak power at 6300 RPM.

An E-wideport / CSA on a Pontiac 461 only peaking at 6300 RPM will be a lazy dog.

[slowbird]

Originally Posted by pastry_chef

Yes.
Well aligned to the oversize head.

I made peak power from a 496 and 11:1 at 7200rpm with the second lobe option. Putting that in a 461 should peak well into the mid 7000rpm range or higher imo.
I like JLMounce recommendation

[pastry_chef]

Originally Posted by slowbird

I made peak power from a 496 and 11:1 at 7200rpm with the second lobe option. Putting that in a 461 should peak well into the mid 7000rpm range or higher imo.

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.

[PAUL K]

I do know what cam will work best but I won't tell you... Fwiw

[ponjohn]

Solid roller or Hyd roller?

[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.

Why were my heads better and it was just a ported Victor so intake doesn't matter.
Did that other Brian dyno? I remember that combo but didn't think he dyno'd

[slowbird]

I sure would think if bigger heads/intake would be run on this engine the rpm peak would be pushed up. So a smaller cam would be needed.
The other thing that's not been discussed is valve events (tighter LS or wider, LC advanced or retarded) that will make a pretty big difference.