Comp's XE Cams

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Dan the man

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Just a question as I don't have any personal experience with these cams. Is it true that the xe cams are hard on the valve train because of their aggressive ramps? Also I read / heard that the rocker arms are usually noisy. Again, I'm only asking a question here. What brand cams still have good quality? Lunati, Howard's? I thought that I read that comp was having trouble with the lobes wiping out easily but I don't know this for a fact.
 
I usually get a custom solid cam from Racer Brown. I have also run Isky cams. Never a problem so far. A little more expensive but the cam is tailored to what I want and quality parts.
 
Valvetrain is a little noisy, hasn't really went through any parts though. It probably has close to 10k miles on it.
 
i have used the comp 268...valve train sounded a bit like a sewing machine and it bothered me.
But after a short period of time i grew to like it!
 
Hi Dan!
Friend;
almost any high lift flat-tappet cam is gonna be "hard" on the stock valvetrain, and often noisy, as compared to the stock parts, which were mostly dead quiet.
How "hard" will depend on how extreme you go, and the willingness of the parts to play nice together, and the level of competency in the assembly of the parts.

The last time we talked, IIRC you just wanted a snappy DD.
At the power-level you were interested in, at that time, this won't be an issue; if the rest of the combo is even just half-decently matched.
In a DD, or in a usage as you described, the absolute power is way less important than having good torque when and where you need it; and to deliver that, with a 318/auto, is gonna be almost entirely dependent on the convertor-stall and gearing.

Absolute power does not happen until all the selected parts come into harmony, which is gonna be an rpm range of about 800rpm, centered somewhere between 4200 of the stock 318 cam, to around 5000 if a cam around factory 340 size. The cams in question here are about 248 to 268 degrees of intake duration, thus a range of 20 degrees. The difference between any two cam sizes is about 7*, so 20 degrees is a range of 3, plus the starting place, so the choices are four, the usual choices being; 248,256,262,268; each cam peaking about 200 rpm higher.
With a stock 318 convertor stalling around 2000 rpm, AND the compression ratio remaining unchanged, and with NO OTHER changes, each cam bigger than 248* is most likely to have LESS take off torque. This means, the power will also be down. The usual cure for this is a higher stall.
The thing is, for a mild 318, and at rpms less than about 2800, each bigger cam is gonna need about 200 rpm more stall just to stay even with the torque of the stock 318.
So even if you keep pace with ever higher stalls, the sub 2800rpm power is hardly keeping pace and the low-rpm performance level is not increasing by much. But at least it's not tanking.
So for a DD that spends most of it's life below 3500; and with only an occasional excursion to maybe 4000, which in Second gear with 2.76s is already over 70 mph; going to a 5000 rpm cam with little or no power increase where you need it below 3500, this is IMO not a good way to go.
The DD needs more power in the operating range that it will be driven in. For a given engine, a bigger cam, by itself, is NOT a good idea. The better idea is to
better match the current engine to the intended application; or, to increase the cylinder pressure, to match the new cam.
Increased cylinder pressure, increases power, EVERYWHERE in the rpm-band.

Here's something that might help you;
Say your engine makes 265 ftlbs of torque at 2000 rpm, going to 290 @2800. This is a realistic progression. Say you have a 2000 stall and an A904, and 2.76 gears. So then, at take off, not including what is going on inside the convertor, to the rear axles is going;
265 x 2.76 x 2.45= 1792 ftlbs.
Lets say all you did was increase the stall to 2800, and swapped in some 3.23 gears. This gear swap by itself is plus 17% . The new number would be;
290 x 3.23 x 2.45= 2295 ftlbs. This is a total increase of 28%
To get the same result, using the 2000 stall and 2.76 gears, but with a bigger cam;
2295 ftlbs/(2.76 x 2.45) = 339 ftlbs . And 339/265 is plus 28% again. A normally aspirated 318 will never ever make plus 28% at 2000 rpm, with no other changes but the cam. Never! Well unless yur coming back to stock from a way too big cam lol.

So then, friend, as I have said before, since, with a bigger cam, you are gonna need gears and a higher stall convertor anyway, you might as well decide on those first, and bolt them up; just maybe, your current engine-combo will be crispy enough for you. It really depends on what is already in your car, and how much hiway driving you intend to do.. For a city car a 2800 and 3.91s is dynomite. That will wake up any old oil-burning smog-era 318, including a 2bbl single exhaust old wheezer. lol Lets say that old wheezer can still make 265 ftlbs @2800; then
265 x 2.45 x 3.91= 2538 to the axles. This is 2538/1792= plus 42%
see what I mean? No cam, by itself, will touch that Plus 42% increase.
Hope this helps
 
Last edited:
Hi Dan!
Friend;
almost any high lift flat-tappet cam is gonna be "hard" on the stock valvetrain, and often noisy, as compared to the stock parts, which were mostly dead quiet.
How "hard" will depend on how extreme you go, and the willingness of the parts to play nice together, and the level of competency in the assembly of the parts.

The last time we talked, IIRC you just wanted a snappy DD.
At the power-level you were interested in, at that time, this won't be an issue; if the rest of the combo is even just half-decently matched.
In a DD, or in a usage as you described, the absolute power is way less important that having good torque when and where you need it, and to deliver that, with a 318/auto, is gonna be almost entirely dependent on the convertor-stall and gearing.

Absolute power does not happen until all the selected parts come into harmony, which is gonna be an rpm range of about 800rpm, centered somewhere between 4200 of the stock 318 cam, to around 5000 if a cam around factory 340 size. The cams in question here are about 248 to 268 degrees of intake duration, thus a range of 20 degrees. The difference between any two cam sizes is about 7*, so 20 degrees is a range of 3, plus the starting place, so the choices are four, namely; 248,255,262,269, each cam peaking about 200 rpm higher.
With a stock 318 convertor stalling around 2000 rpm, AND the compression ratio remaining unchanged, and with NO OTHER changes, each cam bigger than 248* is most likely to have LESS take off torque. This means, the power will also be down. The usual cure for this is a higher stall.
The thing is, for a mild 318, and at rpms less than about 2800, each bigger cam is gonna need about 200 rpm more stall just to stay even with the torque of the stock 318.
So even if you keep pace with ever higher stalls, the sub 2800rpm power is hardly keeping pace and the performance level is not increasing by much. But at least it's not tanking.
So for a DD that spends most of it's life below 3500; and with only an occasional excursion to maybe 4000, which in Second gear with 2.76s is already over 70 mph, going to a 5000 rpm cam with little or no power increase where you need it below 3500, this is IMO not a good way to go.
The DD needs more power in the operating range that it will be driven in. For a given engine, a bigger cam, by itself, is NOT a good idea. The better idea is to
better match the current engine to the intended application; or, to increase the cylinder pressure, to match the new cam.
Increased cylinder pressure, increases power, EVERYWHERE in the powerband.

Here's something that might help you;
Say your engine makes 265 ftlbs of torque at 2000 rpm, going to 290 @2800. This is a realistic progression. Say you have a 2000 stall and an A904, and 2.76 gears. So then, at take off, not including what is going on inside the convertor, to the rear axles is going;
265 x 2.76 x 2.45= 1792 ftlbs.
Lets say all you did was increase the stall to 2800, and swapped in some 3.23 gears. This gear swap by itself is plus 17% . The new number would be;
290 x 3.23 x 2.45= 2295 ftlbs. This is an increase of 28%
To get the same result, using the 2000 stall and 2.76 gears, but with a bigger cam;
2295 ftlbs/(2.76 x 2.45) = 339 ftlbs . And 339/265 is plus 28% again. A normally aspirated 318 will never ever make plus 28% at 2000 rpm, with no other changes but the cam. Never!

So then, friend, as I have said before, since, with a bigger cam, you are gonna need gears and a higher stall convertor anyway, you might as well decide on those first, and bolt them up; just maybe, your current engine-combo will be crispy enough for you. It really depends on what is already in your car, and how much hiway driving you intend to do.. For a city car a 2800 and 3.91s is dynomite. That will wake up any old oil-burning smog-era 318, including a 2bbl single exhaust old wheezer. lol Lets say that old wheezer can still make 265 ftlbs @2800; then
265 x 2.45 x 3.91= 2538 to the axles. This is 2538/1792= plus 42%
see what I mean? No cam, by itself, will touch that Plus 42% increase.
Hope this helps
Thanks for the information. I'm hoping to get in contact with the owner of the 1972 duster that I'm interested in. Unfortunately the wife got sick and she's my main priority. I was thinking about either 3.23 or 3.55 gears, wouldn't those 3.91's make the 318 sign going down the highway? I'm going to be busy as the duster still has a w barrel carburetor and single exhaust. I thought about a edelbrock 500 avs2 and a weiand stealth or a edelbrock performer intake. Most likely I'll be staying with stock exhaust manifolds for a while, dollars lol.
.
 
Hi Dan!
Friend;
almost any high lift flat-tappet cam is gonna be "hard" on the stock valvetrain, and often noisy, as compared to the stock parts, which were mostly dead quiet.
How "hard" will depend on how extreme you go, and the willingness of the parts to play nice together, and the level of competency in the assembly of the parts.

The last time we talked, IIRC you just wanted a snappy DD.
At the power-level you were interested in, at that time, this won't be an issue; if the rest of the combo is even just half-decently matched.
In a DD, or in a usage as you described, the absolute power is way less important than having good torque when and where you need it; and to deliver that, with a 318/auto, is gonna be almost entirely dependent on the convertor-stall and gearing.

Absolute power does not happen until all the selected parts come into harmony, which is gonna be an rpm range of about 800rpm, centered somewhere between 4200 of the stock 318 cam, to around 5000 if a cam around factory 340 size. The cams in question here are about 248 to 268 degrees of intake duration, thus a range of 20 degrees. The difference between any two cam sizes is about 7*, so 20 degrees is a range of 3, plus the starting place, so the choices are four, the usual choices being; 248,256,262,268; each cam peaking about 200 rpm higher.
With a stock 318 convertor stalling around 2000 rpm, AND the compression ratio remaining unchanged, and with NO OTHER changes, each cam bigger than 248* is most likely to have LESS take off torque. This means, the power will also be down. The usual cure for this is a higher stall.
The thing is, for a mild 318, and at rpms less than about 2800, each bigger cam is gonna need about 200 rpm more stall just to stay even with the torque of the stock 318.
So even if you keep pace with ever higher stalls, the sub 2800rpm power is hardly keeping pace and the low-rpm performance level is not increasing by much. But at least it's not tanking.
So for a DD that spends most of it's life below 3500; and with only an occasional excursion to maybe 4000, which in Second gear with 2.76s is already over 70 mph; going to a 5000 rpm cam with little or no power increase where you need it below 3500, this is IMO not a good way to go.
The DD needs more power in the operating range that it will be driven in. For a given engine, a bigger cam, by itself, is NOT a good idea. The better idea is to
better match the current engine to the intended application; or, to increase the cylinder pressure, to match the new cam.
Increased cylinder pressure, increases power, EVERYWHERE in the rpm-band.

Here's something that might help you;
Say your engine makes 265 ftlbs of torque at 2000 rpm, going to 290 @2800. This is a realistic progression. Say you have a 2000 stall and an A904, and 2.76 gears. So then, at take off, not including what is going on inside the convertor, to the rear axles is going;
265 x 2.76 x 2.45= 1792 ftlbs.
Lets say all you did was increase the stall to 2800, and swapped in some 3.23 gears. This gear swap by itself is plus 17% . The new number would be;
290 x 3.23 x 2.45= 2295 ftlbs. This is a total increase of 28%
To get the same result, using the 2000 stall and 2.76 gears, but with a bigger cam;
2295 ftlbs/(2.76 x 2.45) = 339 ftlbs . And 339/265 is plus 28% again. A normally aspirated 318 will never ever make plus 28% at 2000 rpm, with no other changes but the cam. Never! Well unless yur coming back to stock from a way too big cam lol.

So then, friend, as I have said before, since, with a bigger cam, you are gonna need gears and a higher stall convertor anyway, you might as well decide on those first, and bolt them up; just maybe, your current engine-combo will be crispy enough for you. It really depends on what is already in your car, and how much hiway driving you intend to do.. For a city car a 2800 and 3.91s is dynomite. That will wake up any old oil-burning smog-era 318, including a 2bbl single exhaust old wheezer. lol Lets say that old wheezer can still make 265 ftlbs @2800; then
265 x 2.45 x 3.91= 2538 to the axles. This is 2538/1792= plus 42%
see what I mean? No cam, by itself, will touch that Plus 42% increase.
Hope this helps
I'm really looking forward to getting the car and start enjoying it. I'm going to stay with the 318 as I'm sure that it will do what I'm looking for. Car is super clean and I don't want to vary from the way it is. I may go with a different set of wheels as it has those dog dish caps on it.
 
Hi Dan!
Friend;
almost any high lift flat-tappet cam is gonna be "hard" on the stock valvetrain, and often noisy, as compared to the stock parts, which were mostly dead quiet.
How "hard" will depend on how extreme you go, and the willingness of the parts to play nice together, and the level of competency in the assembly of the parts.

The last time we talked, IIRC you just wanted a snappy DD.
At the power-level you were interested in, at that time, this won't be an issue; if the rest of the combo is even just half-decently matched.
In a DD, or in a usage as you described, the absolute power is way less important than having good torque when and where you need it; and to deliver that, with a 318/auto, is gonna be almost entirely dependent on the convertor-stall and gearing.

Absolute power does not happen until all the selected parts come into harmony, which is gonna be an rpm range of about 800rpm, centered somewhere between 4200 of the stock 318 cam, to around 5000 if a cam around factory 340 size. The cams in question here are about 248 to 268 degrees of intake duration, thus a range of 20 degrees. The difference between any two cam sizes is about 7*, so 20 degrees is a range of 3, plus the starting place, so the choices are four, the usual choices being; 248,256,262,268; each cam peaking about 200 rpm higher.
With a stock 318 convertor stalling around 2000 rpm, AND the compression ratio remaining unchanged, and with NO OTHER changes, each cam bigger than 248* is most likely to have LESS take off torque. This means, the power will also be down. The usual cure for this is a higher stall.
The thing is, for a mild 318, and at rpms less than about 2800, each bigger cam is gonna need about 200 rpm more stall just to stay even with the torque of the stock 318.
So even if you keep pace with ever higher stalls, the sub 2800rpm power is hardly keeping pace and the low-rpm performance level is not increasing by much. But at least it's not tanking.
So for a DD that spends most of it's life below 3500; and with only an occasional excursion to maybe 4000, which in Second gear with 2.76s is already over 70 mph; going to a 5000 rpm cam with little or no power increase where you need it below 3500, this is IMO not a good way to go.
The DD needs more power in the operating range that it will be driven in. For a given engine, a bigger cam, by itself, is NOT a good idea. The better idea is to
better match the current engine to the intended application; or, to increase the cylinder pressure, to match the new cam.
Increased cylinder pressure, increases power, EVERYWHERE in the rpm-band.

Here's something that might help you;
Say your engine makes 265 ftlbs of torque at 2000 rpm, going to 290 @2800. This is a realistic progression. Say you have a 2000 stall and an A904, and 2.76 gears. So then, at take off, not including what is going on inside the convertor, to the rear axles is going;
265 x 2.76 x 2.45= 1792 ftlbs.
Lets say all you did was increase the stall to 2800, and swapped in some 3.23 gears. This gear swap by itself is plus 17% . The new number would be;
290 x 3.23 x 2.45= 2295 ftlbs. This is a total increase of 28%
To get the same result, using the 2000 stall and 2.76 gears, but with a bigger cam;
2295 ftlbs/(2.76 x 2.45) = 339 ftlbs . And 339/265 is plus 28% again. A normally aspirated 318 will never ever make plus 28% at 2000 rpm, with no other changes but the cam. Never! Well unless yur coming back to stock from a way too big cam lol.

So then, friend, as I have said before, since, with a bigger cam, you are gonna need gears and a higher stall convertor anyway, you might as well decide on those first, and bolt them up; just maybe, your current engine-combo will be crispy enough for you. It really depends on what is already in your car, and how much hiway driving you intend to do.. For a city car a 2800 and 3.91s is dynomite. That will wake up any old oil-burning smog-era 318, including a 2bbl single exhaust old wheezer. lol Lets say that old wheezer can still make 265 ftlbs @2800; then
265 x 2.45 x 3.91= 2538 to the axles. This is 2538/1792= plus 42%
see what I mean? No cam, by itself, will touch that Plus 42% increase.
Hope this helps
How's the weather there in Canada my friend? I'm. Going to re read your post on gear ratios. I'm fairly good with math but sometimes things take awhile for me to understand.
 
I was thinking about either 3.23 or 3.55 gears, wouldn't those 3.91's make the 318 sign going down the highway? I'm going to be busy as the duster still has a w barrel carburetor and single exhaust. I thought about a edelbrock 500 avs2 and a weiand stealth or a edelbrock performer intake. Most likely I'll be staying with stock exhaust manifolds for a while, dollars lol.
.
if you plan on driving the car, as in on the highway and not just around town, skip the 3.90's entirely and go for either the 3.23 or 3.55

personally i'd say 3.23 is the best compromise of having something that's got a little bite around town but won't be too tall for the freeway. and that will play nice with the dual plane and small four barrel.

keep the cam mellow and no matter who the mfgr is, you should have good results.
 
I have read some where that the closing ramps are what cause all the noise as the exhaust valve closes fast.
 
Hwy driving? 3.23’s and no higher unless an overdrive transmission is used.
 
How's the weather there in Canada my friend? I'm. Going to re read your post on gear ratios. I'm fairly good with math but sometimes things take awhile for me to understand.
Best winter ever!
I've never in my life (70+ years) seen anything like it!. Warm all the time. Even night time temps hovering near zero, and very little snow. The fields are currently bare, with only a little snow in the ditches.

I just noticed, St Louis is about 16 hours nearly due South from my place; and I bet it's warmer up here this winter, lol.

I'm 70 now so retired last fall. I got nothing but time from here to the grave; so patience is my middle name. Feel free to PM me, I made some room in my inbox.
 
Best winter ever!
I've never in my life (70+ years) seen anything like it!. Warm all the time. Even night time temps hovering near zero, and very little snow. The fields are currently bare, with only a little snow in the ditches.

I just noticed, St Louis is about 16 hours nearly due South from my place; and I bet it's warmer up here this winter, lol.

I'm 70 now so retired last fall. I got nothing but time from here to the grave; so patience is my middle name. Feel free to PM me, I made some room in my inbox.
K. Thanks. I may do that soon
 
Hwy driving? 3.23’s and no higher unless an overdrive transmission is used.
I don't disagree, however tire height can play a factor. With a 27 or 28" tire, you can easily get away with 3.55's. Additionally, a 4 speed, or lock up auto make a difference.

One thing about gearing without OD, it is a game of calculated compromises.
 
I don't disagree, however tire height can play a factor. With a 27 or 28" tire, you can easily get away with 3.55's. Additionally, a 4 speed, or lock up auto make a difference.

One thing about gearing without OD, it is a game of calculated compromises.
You guys talk about the use of a overdrive transmission, which one, what year?
 
You guys talk about the use of a overdrive transmission, which one, what year?
I do not have an OD, I run an A833 with a 3.09:1 first gear and 1:1 4th. This allows the use of a 3.23 gear without losing a bunch of 1st gear multiplication. 3.55's are also fun with this setup.

A Gear Vendors, or Passon Hemi OD look appealing to me as I don't want to cut up a factory 340 car.
 
I don't disagree, however tire height can play a factor. With a 27 or 28" tire, you can easily get away with 3.55's. Additionally, a 4 speed, or lock up auto make a difference.
True. Though it allows you to get away with only so much. While the difference is huge between a stock 24& change height tire & a 28 inch tire, this also leads to a compromise somewhere.
One thing about gearing without OD, it is a game of calculated compromises.
Absolutely! The first year drop is big, 2->3 is normal, OD is a bit of a drop but fine IMO for that Hwy / Interstate cruise speed. A compromise I can live with.
You guys talk about the use of an overdrive transmission, which one, what year?
An early linkage activated, Hyd. early version, the A-500.
You do not want the electrical avtivated OD since a computer is needed though I’m sure someone has figured out how to get around it.

If it works s a manual trans, the MoPar 4spd OD is about the same gear ratios within and will feel about the same.

Both “3rd” gear ratios are a 1:1 drive.
 
I do not have an OD, I run an A833 with a 3.09:1 first gear and 1:1 4th. This allows the use of a 3.23 gear without losing a bunch of 1st gear multiplication. 3.55's are also fun with this setup.

A Gear Vendors, or Passon Hemi OD look appealing to me as I don't want to cut up a factory 340 car.
Unfortunately I can't use a 4 speed due to the arthritis in my left hip
 
I have read some where that the closing ramps are what cause all the noise as the exhaust valve closes fast.
There are asymmetrical lobes out there that open the valve quickly but give it a softer ride on the way down. Supposed to help slightly with rpm and power through increased valve train stability.
 
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