Thread: Another Cam Suggestion

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I have the Magnum 280 in my 383, and for me, it is just right. In a 350, it would be a little lumpier than I like personally, but that's a matter of prsonal preference. The Magnum series is often overlooked because of the popularity of the XE series, but the Magnum cams make great power and torque, and you can use them with a little more static compression than the XE cams.

Thanks for the feedback guys !

Thumpr cam is now out, Looking into the Edelbrock e-tec 200 and
XE 256H .447/.454 1,000-5,800 rpm
XE 268H .479/.480 1,800-5,800 rpm
Mag 280H .480/.480 2,000-6,000 rpm

Now I need roller rockers, should I get 1.5 or 1.6 ?

What benefits will that give me other than more lift with the 1.6?

Just a rookie learning.

Originally Posted by kool

Thanks for the feedback guys !

Thumpr cam is now out, Looking into the Edelbrock e-tec 200 and
XE 256H .447/.454 1,000-5,800 rpm
XE 268H .479/.480 1,800-5,800 rpm
Mag 280H .480/.480 2,000-6,000 rpm

Now I need roller rockers, should I get 1.5 or 1.6 ?

What benefits will that give me other than more lift with the 1.6?

Just a rookie learning.

There is no need to go with 1.6 rockers if this is a street engine. Now if you were going to be drag racing, that is a different story. You might also take a look at CompCams XE 262H. The XE 256H is a little small to really get the benefit of the Edelbrock heads you are considering. The XE 262H and 268H are popular grinds, and past comments from people using these grinds in 350's have been very positive. The 268H is a more aggressive grind but it should work fine with your 2200 stall converter. With the Magnum 280, you might want a little more stall than 2200. The 268H definitely has a nice sound that I think you would like.

Thanks Lynn!

I'm going to look into the XE 268 H (CL12-242-2).

I was reading this article that was using this cam. Anything you might want to point out for me?

REALLY appreciate this help Lynn.

http://www.compcams.com/information/...HP0401-001.asp

Here is the other article they mention in the first article.

http://www.compcams.com/Community/Ar...?ID=-548756935

Originally Posted by kool

Thanks Lynn!
I'm going to look into the XE 268 H (CL12-242-2).
I was reading this article that was using this cam. Anything you might want to point out for me?
REALLY appreciate this help Lynn.
http://www.compcams.com/information/...HP0401-001.asp

Just a couple of points to help with your education.
Since the reformulation of motor oils and the removal of extreme pressure lubricants, it is an extremely iffy proposition to run a flat tappet cam. Howards has some acceptable hydraulic roller grinds that will retrofit into an early block for less than $500. If you think $500 sounds expensive, just wait until you frag a flat tappet cam and have to yank the motor all the way down to a bare block again to remove all the shrapnel from the oil galleys.

Of course, a much better alternative is to begin with a roller block. '96-'00 Chevy trucks and vans used a Vortec 5700 350, regular production order number L31. The heavier duty models of these motors used a 4-bolt main, but you won't need 4 bolts at the power level you're considering with this build. I have found short blocks here in Phoenix for $200, although they are beginning to get a little pricey as the word on them gets around. You can re-use (in most cases) the factory roller tappets, dog bones and spider, rods and crank, having to purchase only the cam of your choice, pistons, oil pump and gaskets.

Use only 1.5 rockers on a street build. 1.6 rockers will add less than 10 hp, but will add considerable stress to the entire valvetrain.

You didn't say what pistons you will be using, but you should pay particular attention to the article you linked about using the D-cup pistons. If the pistons you are using have this configuration, then you are good to go. If they have a full circular dish with very little flat area on the crown to mate up with the underside of the head, then you will not be building the optimum motor and may experience some difficulty running on lesser grades of fuel when using optimal ignition timing. I have included photos of a less-than-optimum crown design dished pistons using a circular dish and a very thin flat area around the perimeter of the crown. Compare these photos with the one in the article and you can see that they used a piston with a considerable amount of flat surface to accomplish a good squish (D-Cup piston).

I have run the XE268H cam in a 9.00:1 350. It is not a lumpy cam and you will more than likely have to drop the idle down pretty low to get any lump-lump at all. It is a great street cam though. Makes good torque to move a heavy car. Now here's the thing. All you guys who are building your first or one of your first motors want the lumpy sound of a race motor. Street motors don't sound like that. Race motors sound like that. If you're building a race motor, then build it 10.5-11.0 to 1 and use a 290 degree cam (240 @ 0.050") and put up with its ill street manners, high stall torque converter, stiff rear gears, transmission cooler and crummy fuel mileage on premium pump gas. You'll be sick of it in a few weeks, but boy oh boy, it'll sound good to the geeks down at the drive-in who don't know any better.

Dump the intake and use a Edelbrock RPM or Weiand Stealth. Either of them will be worth 40 hp over the manifold you have now. You didn't say about the headers, but use only full length, tuned headers. Block huggers and other shorty headers are a waste of money in my opinion. You might just as well use those fosdick OEM cast iron manifolds.

12cc pistons with zero deck, 64cc heads and 9cc gasket will yield 9.55:1 SCR. 18cc pistons with zero deck, 64cc heads and 9cc gasket will yield 8.99:1 SCR.

Oh, and I use "fosdick" a lot. It is synonymous with bogus or lame. Fosdick was a character in the Dick Tracy comic strips.

Oh yeah, about heads. Here is a great head for the money. 0.550" max valve lift (street friendly). Will make 400 hp, 450 ft/lbs @ 9.5:1 SCR with a mild cam.
http://www.summitracing.com/parts/EDL-5089/

Scorpion makes a high-quality roller rocker arm with roller tip and roller fulcrum that is affordable. Don't be fooled by the Comp rockers that us a roller tip and ball/socket fulcrum. Fosdick.

The motor will be much easier to drive with a vacuum-secondaries carb. The rule of thumb is....vacuum secondaries if the converter stalls at less than 3000. Double pumper if the converter stalls at over 3000 or if the trans is a stick.

Lots of great reading techinspector1 !

The way I look at it, post a question and real people give their real world experiences, not like advertisements that just sell you stuff. Real good info and thanks again.

I do have the KB-142-030, the d-cup piston, going with 1.5 rockers, sold on the e-street heads, (idle-5500 rpm), can't believe I dismissed them, XE-268-H (1,800-5,800 rpm), or XE-274-H (2,000-6,000 rpm) kind of undecided.

Most likely the XE-268-H, rpm closer to heads and stall.

You mentioned that the oil formulation isn't there anymore for use with flat tappet cams like it once was. What oil do you reccomend for break in and regular oil changes.
Oh, by the way...I live in Canada....eh?

Feel free to comment more, will be ordering stuff in a couple of weeks!

I am no cam guru and I am not sure of the static compression ratio you have with your combo ,but if it fits into the compression you will have ,The XE-262-h is a great cam ,with a set of rhodes or similar lifters to gain even more torque.

The rhodes lifters will kill off some of the lope sound ,but a lower idle speed will cure most of that.
I set my lifters kinda tight with the rhodes ,close to a solid lifter ,so it kinda loses some of the bleed down at low rpm,still keeps most of the lope ,but gives me more lift and duration at the upper rpms.

Originally Posted by kool

Feel free to comment more, will be ordering stuff in a couple of weeks!

OK, I'll comment more. DO NOT USE A FLAT TAPPET CAMSHAFT, REPEAT, DO NOT USE A FLAT TAPPET CAMSHAFT.
If you were aware of the number of flat tappet cams I see roached, you wouldn't even consider one. It's not just the fact that the cam and lifters are ruined and you have to buy them again, it's the fact that the motor has to be removed, completely torn down and all cracks, crevises and oil galleys must be cleaned just like they were when you first put the motor together. So, there's the cost of new cam and lifters, all new gaskets, all the cleaning, re-assembly and the possibility that it will happen all over again. I know there are those of you who have successfully used a flat tappet camshaft, or know someone who has, but everything must be absolutely perfect to prevent wiping a lobe. It's just not worth the gamble when a roller hydraulic camshaft and roller lifters aren't that much more money. I'm going to suggest a Howard's CL110235-12 retrofit cam for you with an intake closing point that will match up with your 8.99:1 static compression ratio. You don't want to use any more cam than this with your low SCR. If you want to use more cam, then change the pistons to 12cc units and use a Howards CL110245. Howards are a little less money than some of the other manufacturers, but still have the reputation of being an excellent product and have been for many years. DO NOT USE A FLAT TAPPET CAMSHAFT.

OK, here's how I would do it.
350 bored +0.030". Cut block decks parallel with main bearing bore for zero deck. (piston crown exactly even with block deck with piston at top dead center), (approximately 9.001" block deck height). The compressed thickness of the head gasket then becomes the squish measurement.
Stock 350 crank, -0.010"/-0.010" OK.
Stock 350 rods with ARP bolts. Re-sized on the big end.
http://www.summitracing.com/parts/ARP-134-6003/
If I wanted to spend a little money on rods, I'd buy Scat I-beam forged Pro Stock rods. They're already clearanced for cam clearance with a stroker crank (3.750") in the event you wanted to use them later on a 383 build and are good to 500 hp.
http://www.summitracing.com/parts/SCA-25700P/
Keith Black hypereutectic D-cup pistons. Use 0.0015"-0.002" piston to wall clearance. Measure piston perpendicular to wrist pin, directly even with bottom of balance pad. Set top ring gap to 0.026"/0.027", second ring to 0.018".
http://www.kb-silvolite.com/kb_car/clearance_pop.php
Aluminum heads require special head gaskets to prevent brinelling of the head.
http://www.pbase.com/image/25091801
Use only the head gasket that Edelbrock recommends. In most cases, the Fel-Pro 1003 is a good candidate, but again, use only the gasket recommended by the manufacturer of the cylinder heads.
http://www.summitracing.com/parts/FPP-1003/
Howard's CL110235-12 retrofit roller tappet hydraulic cam and kit. 214/218, 270/280, 0.488"/0.495", 112 degree lobe separation, cam timing events 0/34/46/-8.
http://www.competitionproducts.com/C...products/1654/
Use whatever thrust button you like. Here's a nice roller button....
http://www.competitionproducts.com/R...ductinfo/8140/
This installs between the nose of the camshaft and the inner timing chain cover to prevent the cam from walking back and forth. Some fellows might prefer to use a solid nylon button to prevent roller bearing failure of the roller button. Lacking information to the contrary, install the button so that the cam will move 0.008"-0.010" in and out. Some fellows will use an aftermarket timing cover that is less susceptible to bending than the stock sheet metal cover as the cam button pushes against it. I've also seen fellows weld a piece of flat metal (like maybe 0.100" thick) onto the inside of a stock cover to strengthen the cover. You can also step up and use a cast cover with a window that will allow easy cam advancing or retarding if you want to. Here's an example....
http://www.summitracing.com/parts/CLO-9-221/
The whole point of the removeable cover is to allow easy access to changing the cam timing. Otherwise, you have to drop the pan to remove the cover to have access to the cam. There are those fellows who will tell you that you can drop the pan down a little to remove the cover without taking the pan off and then work the pan back into position by cutting off a little of the pan rails at the front. I have not been able to do this successfully without having an oil leak at the front after the operation. Do whatever you think is best. If you don't plan on playing around with cam timing, then use a conventional stamped steel front cover with the proper button clearance.

OK, that builds the short block.

I think you have made a good decision to go with the E-Street heads. The valve springs will work well with the cam I have suggested for you. If you can see your way clear to spend a little money on rocker arms, I would highly recommend the Scorpion 1.5 rollers for use with 3/8" studs. The value of these rockers is in the fact that the ratio is correct and that the fulcrum point is roller bearing. Never mind the roller tip, it has virtually no value from a performance standpoint. Standard stamped steel rocker arms will vary from the as-designed ratio by as much as 6 or 7 percent. In other words, a steel rocker could actually be 1.4 rather than 1.5.
http://www.summitracing.com/parts/SCC-SCP1000
I've been playing with my DynoSim software for almost a year now and every street or street/strip build I run through it will make the most hp and torque with a dual-plane, high-rise intake manifold such as the Edelbrock RPM or Weiand Stealth. You will not need more than a 650 carb for your application. Forget those fosdick oil-soaked air filters in my opinion. Use a dry element, minimum 3" tall by 14" diameter.
I might mount an electric pump and good cartridge filter back near the tank, then plumb in a return regulator with a return line to the tank. Out of the regulator, you need only run one 1/2" line to the carb. Set the regulator to max 5 1/2 lbs for a Carter AFB or Edelbrock Performer and 6 1/2 lbs max for a Holley. Not sure about Barry Grant. Call them to find out. If you don't get the fuel pressure under control, you will have tuning nightmare from hell.

Most of you young fellows have been raised with EFI, where more pressure makes more hp. That is not the case with carburetors.

I like a manual choke and usually install them with a microswitch on the choke plate that powers a dash light to show me that the choke is on or off. I do not trust an electric choke. I want to know definitely where the choke plate is at all times.

Use a good set of long-tube equal-length headers with 1 5/8" diameter primary tubes. You can use 1 3/4" tubes to advantage on 383 and larger motors, but 350 and under will work best with 1 5/8". Fabricate an "X" or "H" pipe immediately after the header collectors, before the mufflers, then run 2 1/4"/2 1/2" pipe to the back of the vehicle. 16 year olds and those who don't know any better will terminate the pipes under the vehicle where the drone will make you crazy after a little while. There will be no performance advantage to running the pipes out in front of the rear tires or terminating the pipes under the car. By the time the exhaust gets back that far, it has cooled and contracted enough that there will be no backpressure from the additional tubing going to the back.

There will be no break-in procedure with the roller cam. Wash the lifters and cam with solvent to remove the shipping grease, oil them well with engine oil, install, crank the motor and drive. You can use any type of off-the-shelf motor oil. You will not need oil additives of any kind.
You already have a 7 qt oil pan. Use a good quality oil pump and make certain the pick-up tube is ABSOLUTELY SECURED to the pump. Weld it if necessary. Increasingly, I am reading of more and more fellows losing oil pressure only to find the pickup laying in the bottom of the pan. Adjust the bottom of the pickup so that there is an air gap between the bottom of the pickup and the bottom of the oil pan of around 3/8". A windage tray will free-up a little horsepower and you may want to custom-fit a crank scraper.
http://www.summitracing.com/parts/MIL-32640/

Send your harmonic damper to these guys to be rebuilt.
http://www.damperdoctor.com/
When you get it back, degree it with a tape after determining top dead center.
http://www.summitracing.com/parts/SUM-162591/
Determine absolute top dead center from these instructions with the motor as a short block on an engine stand.....
http://www.iskycams.com/camshaft.php
Make sure you use the front timing cover during the top dead center operation that you will run on the motor after it is together. There are 3 different locations for timing tabs, so if you use a different cover when you bolt the motor together, your entire operation to find and use TDC for ignition timing the motor could be a waste of time.
Set initial timing at the crank to 16 degrees BTDC. Use a timing kit for your distributor that will give you an additional 18 degrees of advance, all in by 2800 rpm's. The motor should not need more than 34 degrees total (initial/centrifugal) ignition advance with the state-of-the-art combustion chambers in the Edelbrock heads. Plug the vacuum advance into the intake manifold, not the fosdick ported vacuum on the front of the carb.

This motor should make excellent power on cat-piss pump gas. I'll run up a DynoSim of the combo when I get more time. Putting this post together has required about 3 hours.