What cam should I get?

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I hear back in the old days kids would unhook a vacuum line so the motor would idle rough and sound like a big cam. Not what I would do but thought I say something
 
The NASCAR guys use a device in tech inspection (I believe it's called a Whistler) that they use to measure the compression ratio without removing the head. Post race inspection of the top finishers still requires a tear down of the engine though.
 
dodge freak said:
I hear back in the old days kids would unhook a vacuum line so the motor would idle rough and sound like a big cam. Not what I would do but thought I say something
Click to expand...

I'm going to pretend I didn't even read that.
 
OK....today I talked to Bob who built the motor. He said that it has a mild Crane cam in it and could not remember the specs since it has been a while. But he does remember that he installed performance type valve springs that he said would handle a larger lift cam than the one that is in it. Also he said the motor is bored .60 over and has 10:1 compression with forged pistons. It has a brand new crank since he said the stock one was bad. I asked him that I wanted to install a bigger cam that had a good lope to it and what would he sugguest and he told me Comp Cam Magnum series. And not to go over 280 duration. Now my question is Magnum series or Xtreme energy cam? What is the main difference? I'm going to check out Comp Cam's web site to see but I wanted to just know what you guys think?
 
The Magnum cam will work best with well ported heads seeing it is a single pattern cam. The extreme series cam will work well with stock heads and better with ported heads. The extra exhaust duration and lift help restrictive exhausts and or heads with less than optimun balance between intake and exhaust flow percentages.

230 @ .050 is plenty for that engine size.
 
rumblefish360 said:
The Magnum cam will work best with well ported heads seeing it is a single pattern cam. The extreme series cam will work well with stock heads and better with ported heads. The extra exhaust duration and lift help restrictive exhausts and or heads with less than optimun balance between intake and exhaust flow percentages.

230 @ .050 is plenty for that engine size.
Click to expand...

Now you saying 230 duration should be max and the engine builder says 280 max. Now I'm just not getting anywhere with this. :sad9:
 
mullinax95 said:
Now you saying 230 duration should be max and the engine builder says 280 max. Now I'm just not getting anywhere with this. :sad9:
Click to expand...

there is two diferent measurements for duration on a cam, there is totalduration wich i gues your engine builder is refering to and then there is duration at 0.050lift wich rumblefish is refering to
a quick search at summits website showed that 230 at 0.050 lift matches the 280duration your engine builder refered to ;) this whas on compcams extrem energy series cams..
hope it helps
 
there are much better cams out there... I had the 284/484 MP cam in the 340 and for just cruising around it was horrible I went back to a "stock"(the smaller Summit cam kit for SB Mopar) and am looking for a bit more now myself wanting to do a cam change and stuff...but that 484 cam aint going back in...for a SB IMO thats more of a strip than street piece. Id look at the Crower 267 HDP or the 271 HDP the 267 is listed as a 273 specific cam plus being a crower it will have /use the Mopar lifter profile.

I believe i got these specs right:

Crower: 267 HDP - 267/271 w 474/485 in a small block - nice lope lots of low end.

271HDP 271/284 485/495 again nice mannered cam. good low mid range.
 
mullinax95 said:
Now you saying 230 duration should be max and the engine builder says 280 max. Now I'm just not getting anywhere with this. :sad9:
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No. What I am saying is 230 @ .050 is alot of cam for a small engine. If your building it to run, then thats fine and alot of cam is what you need. If your building to cruise, you'll need less cam.
A 230 @ .050 cam should provided plenty of power.
Now depending on how the rest of your car is set up and your overall plan is, it could be just right. The rest of the info you never provided. Lets get some facts here.
Cars weight
Gear ratio (You'll end up with)
Tire size (You'll end up with)
Are you 1/4 mile racing. In example, Mikel Beck runs a 360 in his Duster with a smaller Crane split cam. Intake duration is 218 @ .050 and he runs in the 12's. I'm sure his idle is mild. A larger engine mellos out a cam of the same size than a smaller engine. IN otherwords, the same cam in a smaller engine sounds more radical.
I also have this cam in my 318, yet to run at the track, though not set up for it. I have 3.21 gears. This same cam should provided a broad power band and work real well with the gears.
A 1/4 mile racer is the last thing this is going to be. Seriously, if it runs hi 14's, that would be just peachy.
The idea is cruisabilty with a nice power upgrade.

The previous suggestions on cam are very good. If you want a "Choop like an axe" sound, use a single pattern cam. Like that 280 Magnum from Comp Cams.
If you want a better running car, use the split duration cams.
It will still chop at idle, but just simply work better.

A cam that chops at idle will have a numerically low centerline and alot of overlap. Bad for low speed performance. Add in a cam to big for the given combo, it just gets worse and kids on bikes will out speed you in the 60'.
 
rumblefish360 said:
Are you 1/4 mile racing. In example, Mikel Beck runs a 360 in his Duster with a smaller Crane split cam. Intake duration is 218 @ .050 and he runs in the 12's. I'm sure his idle is mild.
Click to expand...

Sure is, nice and mild. You can hear it here, both at idle and full throttle:

http://www.youtube.com/watch?v=gsLtaFXwNdE
 
rumblefish360 said:
Now depending on how the rest of your car is set up and your overall plan is, it could be just right. The rest of the info you never provided. Lets get some facts here.
Cars weight
Gear ratio (You'll end up with)
Tire size (You'll end up with)
'.
Click to expand...

Tire Size: 235/70R15 (what I have now)
Section Width: 9.25 in 235 mm
Overall Diameter: 27.95 in
Sidewall Height: 6.47 in
Radius: 13.97 in
Circumference: 87.80 in 2230.1 mm
Revs per Mile: 744.1

Tire Size: 275/60R15 (what I will go with after new wheels not much difference in diameter)
Section Width: 10.82 in 275 mm
Overall Diameter: 27.99 in 710.94 mm
Sidewall Height: 6.49 in 164.84 mm
Radius: 13.99 in 355.34 mm
Circumference: 87.93 in 2233.4 mm
Revs per Mile: 743.1

Cars weight: 3500 gvw

Gear raito: I don't know... but it isn't in the 4.10 range or 4.56 I also do not have a tach yet. Feels like 3.21,3.55

Transmission: manual 4-speed

Intended use: Street racing and car shows

273 new rebulid bored .60 over
10:1 compression
Crane cam (specs ????)
Headman headers
Flowmaster 40s
Performer intake
500 cfm Edlebrock carb
Better than stock valve springs
Accel 300+ ignition (multi strike,rev limiter)
 
duster340 said:
there is two diferent measurements for duration on a cam, there is totalduration wich i gues your engine builder is refering to and then there is duration at 0.050lift wich rumblefish is refering to
a quick search at summits website showed that 230 at 0.050 lift matches the 280duration your engine builder refered to ;) this whas on compcams extrem energy series cams..
hope it helps
Click to expand...

Yes I noticed the difference and I to assumed this is what he was talking about. Not to use the 0.50 lift deal.
 
284 cam is gonna suck in that car. I just took one out of my 360 and it was too much cam for cruising. The RPM range of 2600 +was just way to high and the car had no jump off the line. I went with the CompCams extreme energy 262 I think. It was recommended by alot of guys on this board and they were dead balls on. The car has alot more power off the line, slight rumble at idle and runs smooth as it ever has. I really dont think youll be disappointed with the Comp Cam XE. Just my 2 cents. Good luck O:)
 
Camshaft Specification Table
Part Number 20-222-3
Engine 1964-2000 Chrysler
273ci-360ci
8cyl.
Grind Number CRS XE262H-10
Description

--------------------------------------------------------------------------------

Intake Exhaust
Valve Adjustment 0 0
Gross Valve Lift 0.462 0.47
Duration At 0.006 Tappet Lift 262 270

--------------------------------------------------------------------------------

Valve Timing At 0.006
Open Close
Intake 25 57
Exhaust 69 21

--------------------------------------------------------------------------------

These Specs Are For The Cam Installed At 106 Intake CL
Intake Exhaust
Duration At 0.05 218 224
Lobe Lift 0.308 0.313
Lobe Separation 110

--------------------------------------------------------------------------------

Recommended Valve Springs 901-16





ADD THIS PAGE TO YOUR FAVORITES

All content presented © COMP Group
 
Pay no attention to advertised cam durations, only pay attention to the ".050 lift duration figures. I would strongly suggest nothing much over 220 Degrees at .050". Max lift will be determined more or less by the duration, probably not much more than .470 or so. Your motor is small in displacement and while higher in compression ratio it wont overcome a much larger cam. It all has to do with your static compressionratio, engine size and cam. A split pattern cam would be my choice. Something like the extreme comp cams or the older but still good crane econopower series. All will work with your springs in all likelyhood. Do a search on 1966 D Dart which the factory screwed together back in 66, this will give you an idea of how much they thought was optimal.
 
Something else to consider. Cam catalog listings group all small blocks together. If you havnt installed a bunch of cams, you may not know the down sides of using one that's too big. The 284 MP cam in a 360, with a bigger bore and more importantly a longer stroke, will have a note at idle, and will feel a little soft unless the engine has decent compression. The same list has the 284 as fitting a 273. It will be a bear to do aything with. The bore is smaller, and the stroke is shorter. You have a small engine. That means a medium size cam on a catalog list acts like a large cam. I've run the Magnum 268 cam before. In a 318 with low compression (bigger port heads) and a 340 with 9.8:1. It has what you want for a noticable idle. But it will not be the best from idle to about 2800. in fact, it may be hard to tune to not feel like a dog under 2K, where you spend a bit of time cruising now. I think the XE262 would be a good choice, but I think your idle will be better than you may want. Why you want a bad idle, I have no idea. For those that "know", a bad idle means you either cant tune it, or assemble a decent engine package.
 
OK
This the cam that Comp Cams recommends when I gave them all of the engine info and car weight etc.... What do you guys think?

Cam Spec Card Inquiry
PART NO. 20-223-3
01 INTAKE MASTER 5443
02 EXHAUST MASTER 5203
03 ENGINE CRS XE268H-10
04 GRIND NUMBER CRS XE268H-10
INT EXH
05 HYDRAULIC Y/N YES 14 DUR @.050 224 230
INTAKE EXHAUST 15 LOBE LIFT .3180 .3200
06 VALVE ADJUSTMENT HYD HYD 16 ROCKER RATIO .00 .00
07 MAX GROSS VALVE LIFT .477 .480
08 DUR @ .006 TAPPET LIFT 268 280 17 LOBE SEPARATI 110.0
18 ADVANCE 4
09 VALVE TIMING OPEN CLOSE 19 VALVE SPRINGS 901-16
@ .006 10 INT 28 60
11 EXH 74 26 DATE SETUP / /
12 THESE SPECS ARE FOR CAM(S) INSTALLED
@ 106.0 INTAKE CENTERLINE
 
My honest opinion is the XE268 is still alittle to big.

The first car a built was a 69 Satalite. It had a 318, 904 and 276 gears. Being a first time hotrodder I swapped in a 280 (228 @.050") .480" lift cam with a 108lsa, a Eddy perf, intake and Eddy 600 carb. The car was a pig, wouldnt idle under 1000rpms and would hardly move. The stock 318 2bbl would walk all over it. It sure sounded good though.

The truth is at the time I knew nothing about tuning a carn or the proper way to time a motor but even if I spent the time sorting the tune out it still would have been to much cam for the motor size, compression, gearing and converter.
 
Also, I love a nasty idle. My new 340 has a solid cam 260/265 @050" It made close to 500hp on the dyno and Im considering swapping in something about 15* smaller for driveabilty.
 
I would get what Comp says. Yeah its big but that motor has small ports so that will help. Hey after a few weeks if you do not like it you could swap cams again!! But with 10.5-1 compression and those small intake ports-compare to the 340-360-it should work ok. I forgot what gears you have but with 3.91's it should be ok.
 
dodge freak said:
I might add that my 318 has Comps HE 268 that gives [email protected] on both intake and exhaust and it seems great till 5300 rpms then the motor is choking. That other cam should be good til 6000 rpms. If thats what you are looking for
Click to expand...

The XE268 (the one I'm looking at) has a Basic Operating RPM Range: 1,600-5,800 RPM. So that is close to 6000 but I'm still concerned about the starting RPM range which is 1,600. I've looked at other cams that start at Idle or 600 RPM and they seem to be like RV or Tow cams. So I think that I am on the right track far as a good performance cam. I still have to learn more about cams before I purchase. So I still have plenty of time and will learn somethings along the way. Lunati has a cam that has 268 duration on the intake and 494 lift on the intake with a staring RPM of 1,800. The Comp cam has 268 duration on the intake and 477 lift on the intake and a starting RPM of 1,600. So I'm like would 200 RPM make a difference and also why is the duration the same but the lift is more on the Lunati? Will the Lunati cam make more horses? Questions, questions??
 
The threoy is a higher lift cam will make more power cause the valves open faster. It will but I do not believe the cam will last as long. Cams wear, even if they do not go flat, the very tops points wear down alittle bit. I would not worry about 200 rpm's. As for 1600 rpm's-I have 3.91 gears and 1600 is gone by fast in 1st or 2nd.

To get the power band lower and still pull good to 5800 Comp has a soild 270 cam which has [email protected] on both intake and exhaust. You need adjustable rockers which the 273 motor had at first. Other wise get the HE 268 cam. Oh it saids starts at 1500 rpms but its much smaller than the XE 268 cam. Can not believe its a 100 rpms differance.

You can drive yourself nuts thinking and looking at all of them. They say when you are not sure go the smaller size. That cause how the motor runs and idles matters more that top end power--for a street motor.
 
mullinax95 said:
The XE268 (the one I'm looking at) has a Basic Operating RPM Range: 1,600-5,800 RPM. So that is close to 6000 but I'm still concerned about the starting RPM range which is 1,600. I've looked at other cams that start at Idle or 600 RPM and they seem to be like RV or Tow cams. So I think that I am on the right track far as a good performance cam. I still have to learn more about cams before I purchase. So I still have plenty of time and will learn somethings along the way. Lunati has a cam that has 268 duration on the intake and 494 lift on the intake with a staring RPM of 1,800. The Comp cam has 268 duration on the intake and 477 lift on the intake and a starting RPM of 1,600. So I'm like would 200 RPM make a difference and also why is the duration the same but the lift is more on the Lunati? Will the Lunati cam make more horses? Questions, questions??
Click to expand...

FWIW, I have the comp XE268H in my 360 with a dual plane intake. It idles at 750 rpms happily, will pull cleanly from 1000 rpm in 4th gear and accelerates with authority from 1500 to 6500 rpm. The car has run a traction limited 13.7 @ 102. I am using magnum heads which use a 1.6 ratio rocker so I am getting .508/.512 lift from this cam in my application. Most of my daily driving with the car is in the 1200-1800 rpm range and I am completely satisifed with the performance in that rpm range.

Both the Comp Extreme Energy and Lunati Voodoo series are about as fast a ramp rate you can get on a flat tappet hydraulic cam these days. The Voodoo is more aggressive and that is how you get the additional lift.
 
mullinax95 said:
The XE268 (the one I'm looking at) has a Basic Operating RPM Range: 1,600-5,800 RPM. So that is close to 6000 but I'm still concerned about the starting RPM range which is 1,600. I've looked at other cams that start at Idle or 600 RPM and they seem to be like RV or Tow cams. So I think that I am on the right track far as a good performance cam. I still have to learn more about cams before I purchase. So I still have plenty of time and will learn somethings along the way. Lunati has a cam that has 268 duration on the intake and 494 lift on the intake with a staring RPM of 1,800. The Comp cam has 268 duration on the intake and 477 lift on the intake and a starting RPM of 1,600. So I'm like would 200 RPM make a difference and also why is the duration the same but the lift is more on the Lunati? Will the Lunati cam make more horses? Questions, questions??
Click to expand...
That basic operating range is just that. Realize smaller engines will not operate in that zone exactly, but more probable, about 200 rpm's higher. Small engines will idle more radicaly than a bigger engine with the same cam.
At 1600 rpm, it is very much like a operating range of 7 - 10 MPH when the power starts coming in due to the cams profile.
(An autos stock stall converter can handle that OK fine, a manual would almost not notice it at all.)
Another thing, the RPM ceiling acts the same way. A large stroke motor like the 360 or stroker 400+ cube engine will make peak power way before that 6000 rpm comes around.

Between cams listings you posted, various manufacures will grind more aggresive ramps into the cam. The same 270 advertised duration cam can have very far different duration @ .050 lift numbers.
The higher the number @ .050 at the same advertised duration is showing you that this cam is a more agressive lifting cam.

On lift, more the merry. But with this and the oether specs, theres limits to it. Even how it performs in identical motors.

In theroy, the Lunati should make more power. (And I thik it will.) It will not if the overall combo is not up to snuff for the cam or the parts used are not up to snuff. A more agressive cam doesn't allways mean more power. If such was the case, the eveyone would be running 1.8 rockers.
Over aggresive lifts can mimic roller cam profiles, but produce less top end power than a milder Hyd. cam.
Hyd. lifters have there limits as well.

Better to error on a smaller cam and be happier over all with the combo not MAXED OUT than be maxed out and unhappy with what becomes overkill for your needs or engine combo and parts.
 
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