What cam should I get?

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Check out Hughes racing tech articles on their web site or better yet give them a call. Their cams are made to work with your 904 size lifter. I had one in my 273 and it worked well. I plan on getting one for my 373 real soon. Bob
 
rumblefish360 said:
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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That is the main concern I have and is exactly why I wanted to learn and ask a thousand questions to find the cam NOT to get. I have shortcuts on my computer for Summit, Comp Cams, Crane, Lunati, and now it seems Hughes will be the next one ( thanks Bob :cussing: ) Just joking! So I am very opened minded and want a cam that is not going to sound stock at idle but yet lay flat out off the line and have good mid-range power/torque also.
 
mullinax95 said:
That is the main concern I have and is exactly why I wanted to learn and ask a thousand questions to find the cam NOT to get. I have shortcuts on my computer for Summit, Comp Cams, Crane, Lunati, and now it seems Hughes will be the next one ( thanks Bob :cussing: ) Just joking! So I am very opened minded and want a cam that is not going to sound stock at idle but yet lay flat out off the line and have good mid-range power/torque also.
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He he he, well, you just keep on asking. Lunati and Hughes offer up front the most aggressive ramp cams. Now comp can make them that way as well. But you must spec it that way. "Max advantage of the lifter diameter."
IMO, it's not needed. But every advantage you take care to take is one step further to maxing out the goal.
 
XE262 cam will be better in that motor In my opinion. My car has never run better with it and I have a 360
3.23 posi rear
4 speed
J-Heads
edelbrock performer RPM intake
TTI headers
Holley 650 dbl pumper carb

My car was almost undriveable with the purple 284 cam. I believe operating range is most impotartant factor in choosing, but thats just me. Good luck in your choice n Git er done!
 
JohnnyJet said:
XE262 cam will be better in that motor In my opinion. My car has never run better with it and I have a 360
3.23 posi rear
4 speed
J-Heads
edelbrock performer RPM intake
TTI headers
Holley 650 dbl pumper carb

My car was almost undriveable with the purple 284 cam. I believe operating range is most impotartant factor in choosing, but thats just me. Good luck in your choice n Git er done!
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Does the idle have a radical sound? Lopey another worlds. The cam shaft in my car just sounds plain after it warms up. I heard a Chevy II today and it sounded good. I wished my ride sounded like that. I don't however want a cam that is to big and thank goodness I've leasoned to the folks on here or I would have already installed the 284. But now it is close to x-mas and my money is going to go else where but when I get by that I'm going to change that sucker out. I might just go ahead and take the cam out and see what size it is and go from there. I will then have a base line to start with. Knowing better where to start.
 
Newbie question here. If I just purchase the cam can I use the same lifters that is in the motor now since it was just rebuilt in July or should I get the cam and lifter kit? I have always thought that it is best to "mate" the cam with the lifters. Thanks
 
mullinax95 said:
Newbie question here. If I just purchase the cam can I use the same lifters that is in the motor now since it was just rebuilt in July or should I get the cam and lifter kit? I have always thought that it is best to "mate" the cam with the lifters. Thanks
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DEFINITELY get a new set of lifters with that new cam. You shouldn't re-use old lifters with a new cam. The $$$ spent may prevent BIG problems as far as premature wear on the cam, possibly failure altogether.

And as for cam selection, go with the 262 Comp. I'm going to be using a Comp XE274 in my motor and I'm running a 6 Bbl., 10:1, and aluminum heads. I'm also running 4.10's and I have a 4 spd. My max. duration @ .050 is only 280.... It's a dual pattern .488/.491 lift cam. I had a .484 in my original motor. It would never idle right and you had to give it a good kick in the *** to get going anywhere. What a dog.....and I had the 6 Bbl. and 2.5" dual exhaust & Flowmasters! The second motor had a .509 lift cam with even more duration and it didn't work either. Sounded like a Pro Stock though...until it blew up.

Go smaller.....the 262 should be fine.
 
You must get new lifters and valve springs that are made for your new cam. The life of your cam will be short if you don't. Bob
 
Yeah I figured that would be true kind of shameful asking such questions. I have found JUST the cam on another forum for sell and it brand new still in the box and it is going cheap! The XE268 (just the cam on Summit) is like 119.95 after the handling fee. If I can get the cam I will buy the XE Lifters that would come with the Cam Lifter kit. But now your saying that came is to big. (pulling hair out and kicking at the floor LOL)

The builder of the motor said that he used high performance valve springs because the cam that is in it is more than stock. I have looked at the valve springs and there is one coil on the outside and one on the inside. The outter spring looks thick to me. So I really don't know much about the springs other than that. I am going to call the fellow that built the motor and ask him some more questions. One is does he remember what the max lift on those springs are.
 
Hello. That Comp Cams XE268 is too big for your 273 in my opinion. Duration at .050 is.224\.230. The Comp Cams high engery 268 has 218\218 degrees of duration at .050. It shouid give you the idle sound you are looking for but will be down on power on the high end due to the low .454 lift. You could use 1.6 ratio rockers and get a .484 lift. That sounds pretty close to what you need. My 273 had 09\14 duration at .050 and .458\ 470 lift at 1.5. It had a stock idle but worked well. Look at Hughes racing tech articles on how to size a cam. Good luck, Bob
 
Man this sucks. Hughes racing says "Maximum lift with stock guide height is 0.450", more lift requires shortening the valve guides. " In that case my moms car has a higher lift than that and it is a toyota. I'm not sure if the guide height has been shortened on my motor but this is getting be a pain in the a$$. When I had my big block Charger all I did was ask a few questions, bought a Purpleshaft cam and BANG I had a radical idle and it hauled booty! And had no valve train problems at all for over 5 yrs.
 
So I'm confused about a little detail here. It's a 10:1 motor, aftermarket cam, a few other goodies, but he ditched the factory adjustable rockers for later model stamped? and on an aftermarket cam at that? Did he use custom cut pushrods?

What heads does your car have? (I didn't see it listed in any of the posts).

I ask because I JUST got done going through all this and installing 273 rockers on my 360 to get the adjustability with my cam.

Use this calculator to find your gear ratio: http://www.thedirtforum.com/gearratiocalc.htm

Go for a spin, note what speed you are going in 4th gear, and what RPMs you are turning. This is for 1:1 automatics, so divide the gear ratio it gives you by the final drive ratio for your 4spd (stock 833?).
 
Its hard to know what to do when you don't know what you have to start with. Thats why valve springs come with a installed height number. So they don't bottom out. I can't believe someone took out the adjustable rockers and replaced them with the stamped set. You could replace them with 1.6 ratio rockers, which will give you 2-4 degrees more duration and some more lift. Or maybe you should leave it alone untill you can pull it and do it right from the ground up. If you have stock 273 heads, the airflow will stall around .450 anyway. Did you ever get the numbers from the cam card? I was frustrated trying to make my 273 into a performance motor as well. Thats why I bought the 340. Bob
 
superdart said:
So I'm confused about a little detail here. It's a 10:1 motor, aftermarket cam, a few other goodies, but he ditched the factory adjustable rockers for later model stamped? and on an aftermarket cam at that? Did he use custom cut pushrods?

What heads does your car have? (I didn't see it listed in any of the posts).

I ask because I JUST got done going through all this and installing 273 rockers on my 360 to get the adjustability with my cam.

Use this calculator to find your gear ratio: http://www.thedirtforum.com/gearratiocalc.htm

Go for a spin, note what speed you are going in 4th gear, and what RPMs you are turning. This is for 1:1 automatics, so divide the gear ratio it gives you by the final drive ratio for your 4spd (stock 833?).
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I don't know why he ditched them if he did. It might have some newer heads on it or something and it came with the stamped. But they are stamped and I guess that is what I will have to use. How can I find out the heads I have? If I remember the part number is below the rockers stamped on the head right? I would do just that to find out what rearend I have but the fellow kept his tach when he sold me the car. I could see after I got it home that there once was a tach. Oh well I guess I will have to buy a nice Auto Meter tach one day. Man I need to just find out everything I don't know for sure what four speed I have yet.
 
bobscuda67 said:
Its hard to know what to do when you don't know what you have to start with. Thats why valve springs come with a installed height number. So they don't bottom out. I can't believe someone took out the adjustable rockers and replaced them with the stamped set. You could replace them with 1.6 ratio rockers, which will give you 2-4 degrees more duration and some more lift. Or maybe you should leave it alone untill you can pull it and do it right from the ground up. If you have stock 273 heads, the airflow will stall around .450 anyway. Did you ever get the numbers from the cam card? I was frustrated trying to make my 273 into a performance motor as well. Thats why I bought the 340. Bob
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I think I just need to tear into the motor and start from there. I'm not getting anywhere because the more I dig the more I need to find out. I asked the fellow today about what was the max lift that the springs could handle and he told me .510 lift. So that is good but I'm not sure about the deck hieght deal in which I shouldn't go over .450 lift. I think I have found out why the 273 has such a mild cam now. All I want is lobey idle. I'm not asking to drag the car just want a good sounding machine.
 
Yes the flow does not improve over a .450 lift but if you go say .480 it will flow max. a longer amount of time. You just want a good sounding idle I think you be happy with comps HE 268 or even a HE 260 but I would get the HE 268, oh it has .454 lift so it should flow great. I do not like 1.6 rockers for a street motor, puts too much stress on everthing, you want a bigger cam than get a bigger cam, those lobes are for a 1.5 lift.
 
dodge freak said:
Yes the flow does not improve over a .450 lift but if you go say .480 it will flow max. a longer amount of time. You just want a good sounding idle I think you be happy with comps HE 268 or even a HE 260 but I would get the HE 268, oh it has .454 lift so it should flow great. I do not like 1.6 rockers for a street motor, puts too much stress on everthing, you want a bigger cam than get a bigger cam, those lobes are for a 1.5 lift.
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The reason I stated .450 lift is because Hughes Racing says "Maximum lift with stock guide height is 0.450", more lift requires shortening the valve guides. " So I it sounds like I'm stuck in the mud. Does anyone know that this true for sure? I mean it states that but I'm not completely sold on that. Another words has anyone had trouble installing a cam that has a higher lift than .450? I would much rather hear someone say that they had a .454 lift came for years and didn't have any trouble with the guide height. Another words I just don't want to tear the heads off! LOL! I would much rather slip in a bigger cam.
 
I never hear that. Maybe 273 are different but I don't think so. Its not that hard to check, the shafts make it easy, just get a dail gauge and depress the valve and see. Its always the springs that are in the way, its racers running over .500 lifts that get in to that problem. I have hear iffy stuff about Hughes racing--like cams that go flat fast--I look at their site and it seems like once you buy 1 item they act like you need everything they sell for your motor to work right. I don't like that thinking, I would stick with Comps or Crane. Comps told you the .480 lift cam would work good and if the motor had a lift problem they would have said something. I would stay away from Hughes myself. Like you said its not a race motor.

Come to think of it, I have a old story from "Hot Rod" mag. back in 1967 call "power mods for Mopars 273" and they put a .510 lift cam in it. They did not do anything the to valve guilds just change the springs , Now they had only .018 of opening clearance which folks today like more but it work for them.You call get it in a book call "Musclecar & HI PO Engines" its Chrysler 273-318-340&360 From Brooklands books, it has old hot rod storys from the 60's and 70's. That Hughes is full of crap it sounds like
 
Save the money you would spend on that 273 and put a 360 in it. You can get the lopey idle you want and still get the car moving below 2500 rpm with the larger engine.
Junkyard 360's are still around cheap and they look just like a 273. Just my dos pesos.
 
Is it true that you only have 105 to 125 pounds of cylinder pressure. If true, I doubt you don't have a 10 to 1 pistons. My 273 had 133 to 144 pounds. Bob
 
I have got into the timing cover and here what I have got to so far. The dots aren't lined up so I don't know what that is all about. The motor is top dead center. Maybe now I can find out what cam is in there and have a base line to start with.

DSC00454.JPG


DSC00453.JPG


DSC00452.JPG
 
Never seen it but maybe those dots should both be on top? If those dots were off that much the motor would not run at all. I am just guessing cause I allways though the crank dot is on top and the cam dot on the bottom but maybe that gear set is different. I do know thats not a double roller set, it just a timing chain like a $17 one. Who cares whats in it now? That timing set is can I say junk? so mabye the cam is a stock replacement. I would just make sure the cam bearings look ok, you should have a good idea now what cam you would like. I bet those valve springs need to go also, get the springs the cam maker says to get. I would change the locks and retainers too.
 
You know what, its fine. You have the motor on the top of the exhaust stroke. The crank needs to be turn one full turn and those dots will line up just fine.
 
dodge freak said:
You know what, its fine. You have the motor on the top of the exhaust stroke. The crank needs to be turn one full turn and those dots will line up just fine.
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Well I was thinking the same thing but let me say this. I am making sure the rotor button is on the #1 cylinder wire and I can see the piston is at it's peak in the bore and also both valves are closed. I have done this about three times and the dot on the cam gear is always at top and the crank gear is on always in the same spot. Does that sound like I have found TDC?
 
Well if you turn the crank one full turn so the two dots are close together is either valve on cly. 1 open? if so then I was wrong and I go back to my first answer, maybe that timing set is different, but I never seen it, but I am no long time engine builder either.
 
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