I have a 72 sb 350 with an auto trans, everything bone stock matching numbers. What would be a good cam I could use to give it a better sound? This is a car that is driven to shows and club events. I was told by a couple other people go with eithr a 327-350 or a 350-350. What can i use to still keep pretty good vacumm but a nice sound with lope. Thanks for all the input in advance.

 

I used the xe 262h in my l48 worked pretty good sounded better. It worked a lot better with A 2400 rpm stall converter.

 

Edelbrock Performer cam, not a clone but the real thing, its the only thing I give credit to that company for.

 

Check out the comp cam xe268h im running that in mine and it works nice with very good street manors did i spell everything right guys

 

thats the cam i was looking at as well.
hows the vacuum for the lights/wiper?
did you change the stall from stock or you a manual guy?
how lumpy is it, you wouldn't have a sound clip of it at idle would ya?

 

im running a tci breakaway 22 to 2400 stall you can tell it has a nice cam in it but its not a nasty sounding cam very street able cam

 

I installed the xe268h in a customer 350 its a good performing cam but probably not the sound your looking for, check out comp cams thumper series

 

Those "thumper cams" sound great but they are murder on the valve train because of the ramps of the lobes to make the sound.
I don't think they make enough zink to protect the lifters from the slam they go thru!!!!

 

The xe268h is not a race car sounding cam

 

I have used the 268 cam and its a great street cam, but the idle is pretty tame. If you want the 'its got a cam' sound, look at Comp Cams Thumper series. Personally I don't care for the lumpy cam sound on a street car. Sounds to me like the guy didn't know what he was doing and put in more cam than he needed.

 

u do realize that cool sound drops mpg by up to ~40%?

 

I have a CC Magnum 280H. You will get the sound you want and vacuum.

 

The thumper lope is caused by a disproportionatly large exhaust duration compared to an already large intake duration. The intake closing point is at the correct point to maintain good cylinder pressure and the exhaust duration is huge in comparison with a tight LSA. The ramp rates at the lobes are less drastic than the XE line of cams and is easier on valvetrain parts.Example:
Thumper 279 TH7
Operating range 2000-5800 RPM
Intake
Adv dur 279
Dur @ .050 227
Lift .479

Exhaust
Adv dur 297
Dur @ .050 241
Lift .465

LSA 107

Here is a link. Notice the intake closing point of 63 degrees. This is what determines cylinder pressures and DCR.
http://www.compcams.com/Company/CC/c...?csid=107&sb=2

Here is a XE series cam with a 64 degree intake closing point. This allows the use on a similar compression engine.
XE 274 H
Operating range 1800-6000
Intake
Adv duration 274
Duration @ .050 230
Lift .490

Exhaust
Adv duration 286
Dur @ .050 236
Lift .490

LSA 110

Here is the link on this cam: http://www.compcams.com/Company/CC/c...x?csid=87&sb=2

Ramp rate is also called hydraulic intensity. You can find this by subtracting the duration @ .050 lift from the advertised duration. As you can see the Hydraulic intensity or "Ramp rate" of the Thumper is 52 intake and 56 exhaust with less lift than the XE cam.
The XE cam ramp rate is 46 intake and 50 exhaust. A much steeper ramp and lift is also quite a bit higher. All these contribute to higher ZDDP level requirements, higher spring pressures, increased valvetrain noise and chance of losing a lobe.
A Hydraulic intensity of 50 is considered the engineering upper limit of safety and durability with a flat tappet cam. Many manufacturers are surpassing these limits as opening and closing the valve faster increases power, vacuum, MPG and other desirable traits with the tradeoff being durability. If you want this type of ramp rate buy a roller cam.

 

Good vacuum with a lope?... Unfortunately the lope comes from valve overlap which is contrary to having good vacuum. 63Mako has made a very good post explaining things, but it still doesn't solve your problem. If you want a lope and good sound, the Thumper is good, but you'll have less mpg than the minimal overlap of the stock cam and vacuum will be less. Accessories will still operate if you can hold 10" Hg or greater, but anything below this will hurt braking consistency if you have power brakes. Of course, you can always convert to manual brakes!

Good luck with your compromise!

 

Somebody that would tell you to use an over 40 year old design is either just plain stupid, doesn't understand cams, or not your friend!

Matt, did bring up a good point about gas MPG and things like thumper cams are all show and no go.

Cams in the 268 -272 range have a hint that they are not stock with 110 lobe centers

 

mako
so what roller has steeper ramps than the xe262 with a 44 ramp rate/hyd intensity? around 218-220 at .050
how does the xe262 use a single spring 110 seat 285 over the nose? I've looked at small roller cams and they always seem to have LAZY ramp rates. Yet require more spring.

 

Go roller.Since your going thru the hassles of a cam change you may as well change over to a roller cam.Did a cam change last year,and now regret not going to a roller cam.Hope to get a few more ponies out of the ol L48.....Looking at a billet crane cam with iron gear.Will post up results after the change out,sometime next month.....

 

Real indication of ramp rate is not some bogus manufacture claimed duration and then out to .050

go to Comp cams lobe profiles and compare the .050 to the .200 and .300 duration numbers

 

Excellent cams!!!


The C5 forum is for you!

63 mako, if a person had to think that much just to take a pee the rivers would all dry up.
If a person EVER even tried to use any of that, that, that, bathtub gin equation they would end up on the C5 forum picking out colored cup holders all day for the ride to the pharmacy at walmart for nerve pills.

 

Sorry if my post is too difficult for you to comprehend. Basicly it says your statement about thumper cams beating your valvetrain to pieces is : and explains why in basic terms.