I know there has been alot of questions on cams lately. I was contemplating on going with an XE 274...but then decided maybe i could go bigger. Anyone have opinions or experience with the XE284, or XE294 hydraulic cams? Would either be streetable? Should I go with the XE294, only because bigger is better? I got a muncie 4speed (probably going Keisler 5speed next spring) and as for rear gears..I am going to rebuild, so different gears will be an option too. Thanks for all the help.

 

Bigger is not always better (especially for street use). Couple of questions that need to be answered:

- What engine? BIgger motors can tolerate more cam. What is radical ina 350 is mild in a 427.
- Intended usage? Street, strip, weekends only, etc.
- RPM usage? I picked a cam that tops out at 5500/6000 rpm and cruises well at 2000 rpm since that is how I drive. I could have gone bigger and made more power but I would have been revving the motor higher and didn't want that.

 

Answers.
383 small block engine...cast crank, forged rods, HyperE pistons, aluminum heads probably AFR 195s, maybe Victor Jr. intake.
intended use for weekend cruising, hit the local 1/8th mile track
RPMs up to 6000+.

 

use Rhoades lifters

 

In one year I had three motors in my Vette. So I have a pretty good back to back comparison.

I'd be driving a hot rodded single plane 355 ci with 3800 stall 700r4 4.11 rear end equiped with a Crane PowerMax 278 cam big heads with 2.055/1.6 valves. Really nice combination for street and strip. 12.40's 1/4's

Well it melted the KB Hyper pistons up after a couple of years of use.

So I bought a 355 ci short block from a friend equiped with a Comp Cams XE274 and put my heads, team G intake, carb, headers back on it. So the only real change was the XE274. I noticed right off it was biased towards the low end somewhat and it had a big mid range charge and then kind of dropped off at 6000 rpm. all easy to explain. The 274 had 110 lobe center and was ground with 4 degrees advance compared to the Cranes wider 112 lobe center and no ground in advance.

So the trade off was a higher power curve of less rpm. Not a good trade off. If I had installed the 274 retarded 4 degrees it might have performed better on the upper rpm. Overall I would not use CC. Your 383 would work better with the addition CI

 

I'm not really a fan of hot cams like the 284 and 294. They are more show than go. they have the radical race sound, but the street manners are bad. Which CC trys to mask with the 4 degrees advance ground in. Excessive overlap kills MPG and real lack of anything under 2000 rpm. Your 4-5 speed can mask lots of deficiencies. Just like my present 3500 stall and 4.11 gears.

IMO – Your better off with high flowing heads and a milder cam. I’ve run three kinds of solid roller cams in my present 383 and I would say that my first mildest 232/240 .620/.644 was the best overall even if it was 30 – 40 hp less

 

I currently run a Lars built 409 (SB 400 bored/stroked) w/ an XE 274. Previously, I was running an XE 268 so I can't compare the 274 to the 284, but here's an article that does. Granted, this is in a SB 400, but I think it's worth a read. The engine in their article is almost identical to what I'm currently running w/ the 274.

http://www.chevyhiperformance.com/te...13/index1.html

I must say that this thing is wicked fast with excellent torque from 1500 RPMs up. The mid-range from 3000 up is where it really comes alive, and it does die-off around 5500 or so. I would definitely go w/ the 284 if I was to do it again (as per the article).

I think this cam would be perfect for your combo especially w/ the Kiesler's low 1st gear.

 

Great article....I definitely am looking for something to still pull after 5000rpm....XE294 might be a bit much sacrifcing alot of lowend...but comparing the xe274 to the 284, nominal low end torque was sacrificed and an overall 15hp gain at the peak....thanks for the Info!

 

Your 383 is a world of difference compared to a 406. I only partially believe car rags This above article link has one possible untruth in it that i picked right out.

They used 1 5/8th headers. Not a big problem You would think. But what the untrained person would know unless they have been around Dart heads is that the Dart 215 heads have physically big intake and exhaust ports. The exhast port are actually bigger than 1 5/8th header pipes. So you explain to me if the "RAG" is really telling the whole truth!

The 284 cam is something like 240/248 @.050 That is technically more duration than my present solid roller which hits hard into my 7500 rpm rev limiter. So I don't believe that it would be a good cam for less than 400 ci.

 

I ran an XE284 in a 383 (well 377 it was a stroked standard bore) with 10/1 comp, alum TFS heads, rams horns and 2.25" duals through flowmasters plus 3.70 and 4 speed, idled a little rough (I liked the sound) but had good power down low and pulled to 6000 hard, never took it above that, I was using Crane fast bleed lifters which are supposed to be similar to rhodes so that might have helped the low end. If not for a rod tapping the block I would still be running it today.

 

If you have two identical cams (lobe ramps, lift, and duration) and one is 110 lc and the other is 112 lc. the larger 112 number has a wider rpm power band that will have a lower peak TQ and HP number, but the overall power numbers if you add 2500,3000,3500.4000,4500,5000,5500,6000, 6500 and devide them by 9 will have a higher average power.

So in a race motor with lots of gears and big number rear end the higher peaks of narrow lobe centers are desirable. just shift allot to keep in the narrow larger power band.

You have got to understand that if a cam card says operating range 2800 - 6500 it doesn't mean that it magically shuts down at 6500. It just means that with a typicle head that it is in a very rapid decline of power drop off. Or the springs are of such light seat pressure that it's gone into valve float and incapable of higher rpm. So if you have high enough flowing heads and correct springs you can continue to make serious HP way above the cam cards operational range.

In your 6000 or so rpm case I would not want a cam that was making peak power at or near red line. You can see in the article with more cubic inches that they intended to be shifting over 6000 which might be 6500+ in a 383 ci of simular parts.

Personally I don't like Comp Cams. Before buying any cam for a stroker motor find out it's Base Circle. I've had problems with CC sending large diameter base circles. You really need cams with less than 1.000 BC. My crane cames have always been .930 inches

 

I run the Comp XE-284 on my 406.Started out with the XE-274 which wiped a lobe in the first 2000 miles. The 274 idled like a stock 350 and ran out of gumption above 5500. Big cubes need big cams. I switched to the XE-284 and run 1.60 rockers.With the RPM intake and 1 5/8" Hookers it pulls to 6500 fairly easy.I plan on a Vic Jr swap in the spring just to try it and make a decision on camming up some more. The idle at 650-700 in gear(Automatic)does shake the fenders a bit,but the off idle pull is strong.Overall not a bad combo.A 383 would be similar.

 

If you'll be running AFR heads, the have very good exhaust flow. You may make more power with a single pattern cam, or one with less of a spread between the intake and exhaust durations. Have you considered a tight lash solid flat tappet? My experience has been that they only need set once a year, unless you're putting a lot of miles on the car. I can set my valves in less than 30 minutes. Given identical duartions, solid cams produce more low-end torque and rev higher than a comprable hydraulic cam.

 

I've used all 3 of these cams in my engine. The XE294 is waay too big IMO for anything less than pro-street. The XE284 is usable if you don't mind not using anything under 3000 rpm, even with my 3.70 rear the engine would buck badly at 1800 rpm unless you were constantly shifting down or on the throttle. The XE274 is a nicer (?) cam for the street and pulls nicely from 1700 rpm on up and hauls a$$ at 2500+. You will need a 10-1 CR and good heads/exhaust for these cams to work properly though. The best all around cam (and I've used 10 different ones in the last 3 years) is the Isky 270/280 megacam. Nice lopey idle (mine will idle at 750 easily) and pulls hard at 1500+ all the way past 6000. No spark plug fouling at all and you will get great vacuum at idle, like 17-19. This cam works well with 9-1+ CR also.

 

Hi there
I have been looking closely at the Isky range for my mild 350 SB, to go with an AFR 195 upgrade.
What is the LSA for your 270/280mega? Isky seems to prefer 108deg, while CC uses 110 and Crane and others like 112.
AFR's apparently like single pattern cams due to the excellent exh port, have you tried the 270, 274 or 280 megacams???
Cheers
Mick

 

Part # is 201271/281-12. LSA is 112. You can look up the specs on Isky's web site.

 

Have any of you guys used Howard's Cams? They look to have quality stuff at reasonable prices. A while ago, they quoted me a really good price on retro-fit roller lifters and cam. $540 for both including new pushrods. I can't really afford the roller right now, so I was looking at this one:


Max Torque 1500-6000rpm .467/.495 lift 280/292 duration 230/240 @.050" 112 lobe seperation.

Really friendly guys and very knowledgeable-unlike CC's "tech line".

BTW, I have a stock GM Goodwrence bottom end, 200cc aluminum Pro Topline 64cc heads and looking to put on an Air Gap or Dart Cool Can intake. Full MSD set up and 1 5/8" Dynomax ceramic coated headers, 2200 stall/BTO 200R4/ 3.55:1 rear gears. Don't mean to hijack your thread- just trying to stay in the game too..

EDIT:
Ugh!!! I just talked to Howard's tech line and he says my 9.4:1 CR isn't enough for the cam I want. He says go with 440/460 lift and 215/225 duration. These guys build race cars, so I suppose the guy knows what he's talking about. Any thoughts?
BTW, he even asked what size rear tires I have.....

 

Just say no to wimpy lifts!

If your heads flow X amount of CFM at .500 and even more at .600 Why would you want to have some .440 lift cam. Especialy if it's a weak H-Flat cam that hardly has the valve at max lift for very long.

 

I don't have any experience with big cams as i've always run the conservative smaller cams for the street. And i see a lot good advice already given. But i think overlap is what really limits the size of cam anyone can use on the local roads/daily cruising.
I like to use David Vizard for a reference and he publishes 50-75 degrees overlap max for hot street machines. This is independent of c.i. or type of head. To figure this take [1/2 intake full duration plus 1/2 exh full duration] minus [2 times the lobe separation angle (LSA)](this converts cam* to crank*). And for single pattern cams its even easier: full duration* - 2 x LSA. My single pattern Crane energizer has 266* full duration and 110 LSA for: 266*-(2 x 110) = 46* overlap.
Yes i think large c.i. mtrs can handle more duration. Yes i think a tighter LSA can make more pwr (Vizard writes 106 max LSA is optimum for 383" mtr but can be larger for better flowing heads). But watch that overlap redshark. cardo0

 

Redshark6974..

I have a 385 with 10.5.1 comp with AFR 195 heads, with the AIR GAP manifold, I have the XE-274 Cam and this thing pulls hard to 6000, I have gone over the 6000 mark, with out much effort, I have 4 SPEED with 355 gears and 275 dunlops out back, and if I am in first gear and bring it to 2800 rpm and then nail the gas, I can get the tires smoking, where the car goes sideways, unbelievable power with this cam, I almost went with the XE-284 but I wanted some low end torque and really didn't care to see 6000rpm..I would rather have a cam thats a tad small than a tad big