Looking for advice on the following cams, if anyone has used them.

http://www.compperformancegroupstore...Category_Code=

http://www.compperformancegroupstore...Category_Code=

This is the cam I currently have in the alum 427 and it is just too much for the street: http://www.compperformancegroupstore...Category_Code=

Has anyone had any experience with either of the first two cams? This car is just a street cruiser, I want plenty of low end torque and a nice rumble thru Stahl headers that dump into 3 inch side pipes with spiral tube inserts. Gearing is currently a Richmond 5 speed with 3.70 rear, but will probably change to a 3.08 rear.

Thanks for your input.

Rex

 

If you listen to David Vizard, you will limit cam duration to approx 270 degrees for a street car. You found out the hard way that bigger is not better. Street driving is street driving, you are maxed out hardly 0% of the time.

I have a mild street cam in my Kirkham and you can't believe how much crap I take from my buddies. But my car has the best street manners and I'm always ready to go on a 200 mile trip, while my "buds" aren't.

You've got a big block, let the inches work for you.
Just my opinion.

 

run the good ole L72 cam...

the car will run fabulous..
you can go 10k between checking valves,
it will make plenty of vaccuum, and have great street manners..

those XR cams... have a ton of valve train noise because of the aggressive lobes.


i'm sure the race guys will chime in with ideas, but for a street cruiser, you can't beat the factory HiPo shafts.

A

 

I have their 286 XE in a flat tappet hydraulic in a 10:1 427 and I cannot imagine anyone considering it to be to much for the street............ so I would guess that a 284 grind would suffice just fine for you.

Other things like a dual plane intake and not to big a carb make a big difference for a good but peppy street cruiser

BTW.........A word to the wise concerning the 850 DP Holley.......... in reality it flows up between 950 -1000 and that is why so many people who buy one end up with real dogs in the lower rpm range. On your motor a well tuned 750 or at the most an 800 would IMO deliver the best street manners for you.

Just my .02

Doug

 

I've tried a few different cams and I will NEVER run another hydraulic anything in a big block. I last had a Comp Cams XE 274, which had an ok idle, and great midrange, but at 5500 RPM it was like someone shut the key off. Then I tried their nostalgia plus LS6 replacement solid cam. It was ok but idled kind of rough. That cam lost a lobe when API changed the standard oil compositions in 2005 and no one told me about the zinc additive being taken out. I'm currently running a Crane solid that's a little bigger than the factory L72 cam. Look for a lobe separation angle of 113 to 116 degrees on whatever you choose our you'll have crap idle with no vacuum.

Unless you've heard recent news about Schubeck solid roller lifters, I;d stay away from solid roller cams, too.

To tell ya the truth, I'm with aaron. I had the L72 cam in my 65 with oval port heads and that was just about the best overall street motor I ever had.

 

Forgot to mention.....................the engine is basically the same as the new Anniversary 427 ZL-1, with the exception of a Holley 750 dp carb. Everything else is the same.......................block, heads, crank, rods (TRW 9.5 : 1 pistons). I had a new stock hyd roller cam (502-502 take out) and should have stayed with it.

Keep your comments coming.................I've got to get this thing ready for the upcoming Hot Rod Power Tour.

Thanks,
Rex

 

If you intend to run a flat tappet, I highly recomment using Rhoads variable duration lifters. If they still make them. They really calm down a big cam downstairs, and I have had no problems going to 6900-7200 rpm. And they seriously improve low end power.

I was running a 588 lift Comp cam in a 454, and it was worse than the ZL1 cam I had in my L88. You needed 1400 rpm at idle in neutral to have enough idle in gear, with a 4000 convertor. I switched to Rhoads lifters, and idle was 1000 in neutral, 800 in gear and 700 with the AC on. Bottom end and midrange improved so much that the car blew off the 10x29 D5 Goodyear slicks that had been sufficient up to that time. Went to a softer compound 10.5x28 Michey Thompson. Engine would pull hard to 7200, but I usually shifted at 6900. My 4100 lb Monte Carlo with 4.10 gear went 11.80 @ 114.12.

I currently run 2 454 Montes with 555/576 Elgin cam with 112 centerline. and Rhoads lifters. One is auto with 3000 convertor, big port 291 heads 850 holley and 4.10 gear. The other is 4 speed, oval port open chamber heads with 2.25/1.88 valves 850 holley and 3.73 gear. Both have 71 LS6 design 9to1 pistons, the auto has forged, the stick has hyperutectic. The gearbox car is faster.

Both cars idle like a stock LS6, when warm, without a lot of lope. I shift around 6700. To me the only drawback is they sound like solid lifters, and I like to walk softly, but carry a big stick, so I would prefer quite lifters.

Other than that I am very happy with them.

Btw, it is not hydraulic lifters that limit rpm, but cam profile and valve springs. Valve float is caused by the springs giving up. The hydraulic lifters then take up the slack left by the springs, and take time to bleed back down, so they get the blame. I lash my hydraulics at 1/8 turn after 0 lash, which helps prevent pump up, and can add several hundred rpm to a hydraulic cam. Been doing this for 30 years without a problem.

 

Can someone help me understand the "mystery" of camshaft duration?

For example, GM lists their specs as follows:

Camshaft lift (in): .527 intake / .544 exhaust
Camshaft duration (@.050 in): 224 intake / 234 exhaust

Duration is listed @ .050 inch

For a "seemingly" similar cam, Comp Cams lists the following

Camshaft lift (in): .521 intake / .540 exhaust
Camshaft duration - advertised duration 288 intake / 294 exhaust
duration @ .050 inch 236 intake / 242 exhaust

The latter cam (Comp) is the one I have in the engine now and it is too wild for the street. I am considering buying a new cam from GM (the first one listed above) that is the std cam in the 502-502 crate engines. However, on paper, they look almost identical.

I need to enroll in "Cams 101". Anybody teaching?

Thanks,
Rex

 

Duration is the number of degrees of crankshaft rotation that the valve is open. Effective duration is measured at .050 lift since that is when the valve is open enough to have effective flow. Overall duration is measured as soon as lift begins. Overlap is the number of crankshaft degrees that both valves are open, If I remember correctly, centerline is the middle of overlap, and refers to the number of degrees before TDC centerline occurs.

Is that cam you have a flat tappet? If so, see my previous post.

 

OK, I knew that, so maybe I need to enroll in "Cams 201", but what about the two cams I listed. Are they actually almost the same identical cams?

Thanks,
Rex

 

Not necessarily. Lobe profiles can be completely different on cams with exactly the same specs. In stock class drag racing, lift and duration are measured against stock specs, but a different profile can give more power. The cam may start and finish at the same degree as stock and lift would be the same, but if you make the ramp steeper, and more rounded, the valve allows more air in, or out. This was called a "cheater" cam back in the day. A roller cam can have a lobe shaped like an oval, whereas a flat tappet would be shaped more like an egg. This is because a roller can go up a steeper ramp, whereas a flat tappet needs a gentler ramp so the side of the lifter does not contact the cam, which would cause rapid failure. What is the centerline? As stated in a previous post centerlines of 114-116 degrees give better idle. Different cam manufacturers use various designs. So cams with similar specs can act quite differently. Chevy cams tend to have more gentle ramps, so their advertised durations were much greater. The ZL1 cam had duration specs of 354/366 degrees, IIRC, yet effective duration was much less.

 

Centerline of GM's cam is 110..................Comp cam is 106.

 

Can someone post a sound clip or a link to one of a Ram Jet 502 or ZZ502 or ZZ427 Anniversary ZL-1 engine running so I can hear the camshaft sound? Looking for the sound of a GM stock hyd roller cam.

Thanks,
Rex

 

Rex, sorry to be crude.. but are you looking for idle sound? or best performance?

the 110 LSA will have much better street manners than the 106 IMHO.

the tighter LSA will make the engine more peaky, the wider makes it broader, and is generally the more acceptable route for a street cam.

I still think that the L72 (while it is a solid cam) is your best bet.
hands down..

i can almost guarantee that while there will be lash, it will still be quieter than the rhodes variable lifters, or the XE series hydraullic cams that comp offers. those suckers are just noisy, and if you are going with a flat tappet, the XE stuff is much harder on the parts than the OE solid cam will be.

you'll be able to go 10-15k without worring about the valves and the motor will run forever.

it is very gentle on closing the valve also so you won't need a valve job in 30k miles either.

I just recently drove an L72 in a camaro, and it was the best of everything... had a nice lopey idle, but not a race idle... (sounded like a stock Hi-Po camshaft) and it made plenty of low end, and pulled to 6500 rpm... everything you'd want from a great street car.

Good luck

Aaron

 

Hi Aaron and thanks for the info. Yes, I'm interested in idle sound, but not just that alone. Also interested in performance to about 5000 RPM, which the engine may seldom, if ever, see. My racing days are behind me now, just looking for something that has a nice sound, is totally streetable, and has lots of low end power. Can't really go with the L72 cam since the heads are already set up for hyd roller cam. Will probably go with the 502-502 cam. Another CF member has contacted me and he has a new one at a fair price. I actually had one (sold it) when I was gathering parts for the engine, but since we couldn't determine actual cam specs, my engine guy preferred going with a NEW cam so he would have the specs, so he talked me into using the Comp cam, which turned out to be waaaaaaaaaaaaaaaaaayyyyyyyy more than I wanted. So now, the engine is in the car, has been fired and run for 20 minutes, and now I am faced with changing out the cam...........with the engine still in the car. Not happy about it, but gotta do it.

Thanks,
Rex

 

Rex,

I am actually getting ready to install the second cam you have there in my 427, the XE 282 HR. I've gone through 2 of their XE 284 hyd flats already and after this rebuild, I've decided to try their hyd roller this time. I was going to back down to their XE 272 hyd flat, since the 284 was pretty extreme on the street. But after some thinking, I decided to spend some more $ and go the hyd roller this time. Also, I wiped a lobe really bad on a flat tappet the first go around, so I am also hoping that the hyd roller provides more durable this time around.

The engine builder should have mine this week, and it will be a couple more weeks until she's running again. Not sure what your time frame is, but I am sure I'll get some video clips of it in a few weeks.

Later,
Rob

 

Thanks to everyone who has chimed in, your help is greatly appreciated.

Here are the two GM cams I am considering. Please review the specs and let me know your thoughts, or better yet, if you have used either and your opinions. Please note the difference in durations and lobe centerlines. As I stated earlier, I am looking for a cam for my 427 ZL-1 with 9.5 : 1 compression, oval port GM alum heads, GM dual plane intake, 750 Holley dp carb. Engine needs to be capable of 900 - 1000 RPM idle, ample vacuum for power brakes, good throaty sound, and good power from idle to 5000 - 5500 RPM, dependable and streetable. I know, I'm asking for a lot.

Thanks,
Rex

This is the one for the 502-502 engine:
Part #12366543
Steel hydraulic roller
I: 224 E: 234
I: .527 E: .544
Lobe centerline 110
For 502/502 special engine. Must use distributor gear P/N 10456413.

This one is used in the 454 & 502 HO and teh new Anniversary 427 ZL-1 engines:
Part #24502611
Steel hydraulic roller
I: 211 E: 230
I: .510 E: .540
Lobe centerline 112
For 454 and 502 HO engines. Must use distributor gear P/N 10456413.

 

either cam should be fine.. actually they aren't very far off from the L72 cam at all either..

good luck

Aaron

 

My Comp hyd roller has 230/236 duration at .050" and ~.560 lift with a 113 LSA and generates 400 ft-lt Tq at the rear wheels at 1500 RPM, and keeps over 400 ft-lb Tq to over 5600 RPM with a 9.5:1 CR. Can't recall the intake lobe CL at the moment.

427 SB, BTW

Can't get much more street friendly than that, and it has an average Tq over that RPM range greater than an L-88.

Doug

 

Rex, you have a PM.