340 max camshaft with exhaust manifolds

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you're jumping all over the place. first bringing up the E4 cam, conflating a number of different ideas, and making odd comparisons. all without explicitly stating what the intended use or idea is for the car, just vague generalities.

anyway, it seems like you've got this well enough in hand so i'm going to excuse myself from any further involvement and just follow along.


My apologies if I wasn't clear enough. Putting together a Saturday night special for my Son, and I listed the options we have.

Not sure why all the hydraulic cam responses.
 
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Why Max, you can run pretty big cams in less than ideal combos circle track guys do all the time.

You want the cam that will give best results for intended purpose of the car .
Poorly stated on my part. Max duration, lift under .500"
 
You pretty much run any cam you want just make less power than with headers, high amount of Overlap generally doesn't like restrictive exhaust and needs collectors to function properly and a restrictive generally likes more exhaust duration. Your not gonna find too many large cam and manifold combos to copy, What ballpark cams you thinking about?
I'm concerned about exhaust reversion. We have several combos and the mildest one is solid lift 230/489.
 
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Call Racer Brown or any decent cam Co. There are a lot of tried and true as well as custom solid cams that don't make it into a catalog.
 
Explosive midrange. Gears aren’t an issue.

Gentlemen,

you realize our competition: Chevrolet, offered 2x4 bbl and stock rear dump exhaust manifolds on a 302 ci with a smog pump! Was this a fluke?

I'm confident Mother Mopar wasn't far behind. The six pack was rated at 1000 cfm. Ma mopar used manifolds on the TA. Seems logical that one could exceed the 340 cam's potential with manifolds...

Poorly stated on my part. Max duration, lift under .500"
I’m guessing you’ll run a gear ratio to suite the cam then?
Same with a converter? Or is this a 4spd manual?
(Sorry for asking… just wanna be clear.)
What does the car weigh and what exact car is this?
Tire size to be determined?
Compression ratio?

The MoPar 6 pack rated on a 2bbl. draw is 1250 cfm.
Converted to a 4bbl. draw, it’s 955 cfm.

You’re listed .500 lift, is this where the stock heads flow rate stops increasing? What heads and valve sizes? Any porting work?
 
As someone mentioned above, the FAST guys use an OEM intake manifold. This is giving up power but there’s enough there to allow a good power maker and it’s awesome because it’s super stealth. I know work goes into the intake you can’t see. But that’s the game, Factory Appearing!!!
 
Call Racer Brown or any decent cam Co. There are a lot of tried and true as well as custom solid cams that don't make it into a catalog

I’m guessing you’ll run a gear ratio to suite the cam then?
Same with a converter? Or is this a 4spd manual?
(Sorry for asking… just wanna be clear.)
What does the car weigh and what exact car is this?
Tire size to be determined?

The MoPar 6 pack rated on a 2bbl. draw is 1250 cfm.
Converted to a 4bbl. draw, it’s 955 cfm.

You’re listed .500 lift, is this where the stock heads flow rate stops increasing? What heads and valve sizes? Any porting work?
72 dart. Gear rations 3.55/3.91/4.30 are at hand. spread-bore intake 800 cfm. 26" is an easy option. 28 might be a little tight.
 
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You pretty much run any cam you want just make less power than with headers, high amount of Overlap generally doesn't like restrictive exhaust and needs collectors to function properly and a restrictive generally likes more exhaust duration. Your not gonna find too many large cam and manifold combos to copy, What ballpark cams you thinking about?
[email protected]. I ran a 230/230 .485 solid in a 289 with 4 speed 3.55 and stock manifolds. Ran fine from bottom to top.
 
72 dart. Gear rations 3.55/3.91/4.30 are at hand. spread-bore intake 800 cfm. 26" is an easy option. 28 might be a little tight.
800 cfm TQ or Holley or Edelbrock?
If you can get 28” under there, I don’t think it a problem on a Dart.
I’m setting up for something similar using a big TQ on a ‘71/72 spreadbore intake, ported heads, kind of a FAST thing but not for competing, same deal, light to light and cruising.

I’m going to be working with an old Hughes engines solid cam, the older solids, HEV 3945 (239/245@050) to help extend the upper rpm range and the ported heads. Out of your gear ratios, I think the 3.91’s would suite the street best as the 4.30’s will be limiting in top end speed and traction may be difficult, MAY…..
It’s all about right foot control. Some people here don’t get that.

I’d look for a cam on a 108 LSA and a duration between 236 & 240 @050 with as much lift as the heads flow well to. If good flowing ports show slowing down after .500, that’s where I’d stop lifting the valve and just try and hang the valve there as long as possible. Also lift it to max height as quick as possible. A cam like this should still work very well with a 91 octane @ 10-1 compression.

Don’t skimp on a converter if you have an automatic trans. You can get great driving converters that also work great on the street.

Focus on making the rotating assembly as light as possible.
 
800 cfm TQ or Holley or Edelbrock?
If you can get 28” under there, I don’t think it a problem on a Dart.
I’m setting up for something similar using a big TQ on a ‘71/72 spreadbore intake, ported heads, kind of a FAST thing but not for competing, same deal, light to light and cruising.

I’m going to be working with an old Hughes engines solid cam, the older solids, HEV 3945 (239/245@050) to help extend the upper rpm range and the ported heads. Out of your gear ratios, I think the 3.91’s would suite the street best as the 4.30’s will be limiting in top end speed and traction may be difficult, MAY…..
It’s all about right foot control. Some people here don’t get that.

I’d look for a cam on a 108 LSA and a duration between 236 & 240 @050 with as much lift as the heads flow well to. If good flowing ports show slowing down after .500, that’s where I’d stop lifting the valve and just try and hang the valve there as long as possible. Also lift it to max height as quick as possible. A cam like this should still work very well with a 91 octane @ 10-1 compression.

Don’t skimp on a converter if you have an automatic trans. You can get great driving converters that also work great on the street.

Focus on making the rotating assembly as light as possible.
236 240 108 with bad flowing heads and those tiny manifolds?
 
800 cfm TQ or Holley or Edelbrock?
If you can get 28” under there, I don’t think it a problem on a Dart.
I’m setting up for something similar using a big TQ on a ‘71/72 spreadbore intake, ported heads, kind of a FAST thing but not for competing, same deal, light to light and cruising.

I’m going to be working with an old Hughes engines solid cam, the older solids, HEV 3945 (239/245@050) to help extend the upper rpm range and the ported heads. Out of your gear ratios, I think the 3.91’s would suite the street best as the 4.30’s will be limiting in top end speed and traction may be difficult, MAY…..
It’s all about right foot control. Some people here don’t get that.

I’d look for a cam on a 108 LSA and a duration between 236 & 240 @050 with as much lift as the heads flow well to. If good flowing ports show slowing down after .500, that’s where I’d stop lifting the valve and just try and hang the valve there as long as possible. Also lift it to max height as quick as possible. A cam like this should still work very well with a 91 octane @ 10-1 compression.

Don’t skimp on a converter if you have an automatic trans. You can get great driving converters that also work great on the street.

Focus on making the rotating assembly as light as possible.
Quadrajet. Easy to copy the Edelbrock air bleed settings. 3.31 like the smaller primaries.
 
I would look for a cam with the intake duration and lift you want (225° at .050, .470-480 lift?) , a wide lobe sep angle to cut down on overlap, and about 15 degrees more exhaust duration to crutch the manifolds.
....or, just call a reputable cam company.
...or somebody like Porter Racing Heads, for a recommendation.
(and I like solid cams too)
 
236 240 108 with bad flowing heads and those tiny manifolds?
There comes a point where the equipment being used is in stone and you just simply ignore what they are and proceed with the build accordingly. Knowing the intake and exhaust is curtailing power and hurting the build, you redesign the camshaft and make the best possible choices elsewhere on the build to help as much as possible.

The F.A.S.T class of racing has proven this. Since he is not going up in cubic inches, the OEM parts are not taxed as much like a big stroker would tax the OEM parts.

Making concessions in camshaft profile and other parts of the engine because of the OEM intake and exhaust manifolds only kills more power and makes for a weaker engine.

You must pay attention to the duration @050 and the overlap (LSA) of the camshaft to make better power than grabbing an off the shelf camshaft. IN ANY APPLICATION!

If you just want to just press the easy button and grab a off the shelf cam, then be happy with your results. When you get a pasting on the street, blame yourself.
I would look for a cam with the intake duration and lift you want (225° at .050, .470-480 lift?) , a wide lobe sep angle to cut down on overlap, and about 15 degrees more exhaust duration to crutch the manifolds.
....or, just call a reputable cam company.
...or somebody like Porter Racing Heads, for a recommendation.
(and I like solid cams too)
A wide LSA is a torque looser. While it’ll give a higher vacuum reading and idle nicer, ask yourself, would you throw away 30 ft. lbs. of torque or more just for a smooth idle?

For a described car the OP has given, a wide LSA is not only the last thing I’d do but I also would make sure the cams profile would stay aggressive and work in my desired RPM range I’m looking for. Lack of vacuum hurting power brakes?
Add a vacuum pump. Double rubber mount it at the front of the car under the battery tray.
 
There comes a point where the equipment being used is in stone and you just simply ignore what they are and proceed with the build accordingly. Knowing the intake and exhaust is curtailing power and hurting the build, you redesign the camshaft and make the best possible choices elsewhere on the build to help as much as possible.

The F.A.S.T class of racing has proven this. Since he is not going up in cubic inches, the OEM parts are not taxed as much like a big stroker would tax the OEM parts.

Making concessions in camshaft profile and other parts of the engine because of the OEM intake and exhaust manifolds only kills more power and makes for a weaker engine.

You must pay attention to the duration @050 and the overlap (LSA) of the camshaft to make better power than grabbing an off the shelf camshaft. IN ANY APPLICATION!

If you just want to just press the easy button and grab a off the shelf cam, then be happy with your results. When you get a pasting on the street, blame yourself.

A wide LSA is a torque looser. While it’ll give a higher vacuum reading and idle nicer, ask yourself, would you throw away 30 ft. lbs. of torque or more just for a smooth idle?

For a described car the OP has given, a wide LSA is not only the last thing I’d do but I also would make sure the cams profile would stay aggressive and work in my desired RPM range I’m looking for. Lack of vacuum hurting power brakes?
Add a vacuum pump. Double rubber mount it at the front of the car under the battery tray.
I thought this was the 273 thread my bad
 
I thought this was the 273 thread my bad
It still wouldn’t matter much. The duration and overlap would be slightly adjusted, equipment dependent. But like I said, the intake and exhaust are hurting the power but THAT Sleeper look is what they’re after. So the intake and exhaust will remain.

Look at it this way, I could go through 100 builds here and pick out 3-5 items just on the big hardware being used and call it insufficient or loosing power because of it.

There is also a thing that the better power maker is making that power upstairs where there not going a lot and/or loosing power down low where they maybe spending more time driving in.

Point is, there are always sacrifices being made in one area or another on darn near every build. A lot depends on what you’re willing to live with and not. What equipment your using and how it makes sense to YOU as the owner or YOU as the guy reading and suggesting the parts for someone else.

I normally don’t rag on people for their choices because it’s there car and there way. The way it should be. Openly asking for advice always brings in opinions and we know what they say about those and butt holes!

:rofl:

I just try and help. Offer my opinion and point of view and thinking. If ya like it, run with it, if not, that’s OK and fine. I just try and make sense and be logical about it to my best.

No one here is out to hurt anyone IMO.
It all comes from a good place. The heart and the want to help.
 
Surely you can chime in on this one. Have any "Reed" grinds that you've used?
That's one brand I've never used. A lot of the guys on the dirt track scene used them when we were doin it. We always used Crane. Reed had it goin on for a while, though. If you're wanting some "good" advice, I would call Jim at Racer Brown and tell him your constraints and see what he says.
 
Never mind…. Carry on.
? It was meant to be a statement of agreement, most would/do sacrifice LSA, majority of cams have that sacrifice built in by selling them on 110-114 + LSA.
 
I agonized over manifolds vs Doug's D453 headers. I finally decided that I couldn't leave 20 hp on the table. Not only that but headers make the exhaust crispy , making its own unique tone that is unmistakable
 

That's one brand I've never used. A lot of the guys on the dirt track scene used them when we were doin it. We always used Crane. Reed had it goin on for a while, though. If you're wanting some "good" advice, I would call Jim at Racer Brown and tell him your constraints and see what he says.
Thank you, Sir!
 
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