I'm building a 496 with the 305 AFR heads(cnc chambers)and eagle rotating assembly and roller everything. The fellow @ AFR that I spoke to recommended a Comp Cam for my set-up. Keep in mind I'm only going to have 10:1 compression. AFR recommended a 290HR Magnum Cam (.232/.232 @.050")with.578/.578 lift.When I called Comp, the tech guy there recommended a custom grind Extreme Energy Cam(.230/.236@.050")with .578/.590 lift. Both have 110 degree lobe seperation angle. Here is a little more info about my engine. I'm using an Air Gap intake, 750cfm Holley DP with no air horn(probably to small), all MSD ignition, and Hooker Super Comp. headers with 2.5" flowmaster exhaust kit. I'm putting it in a 69 Chevelle and backing it with a Tremec 5-speed. My rear-end gear is a 3.31 right now, and I want to see how it does with the Tremec before tackling a gear swap. Any help with my cam selection problem will be greatly appreciated. Thanks!!!!

I'm not into this at all but if I was to put a roller in my about 9.8 to 1 CR., mild mannered, CC 282S solid cammed, 496"er, I would step up to a good old CC 288AR solid Street roller and be done with it.

I figure the sucker should produce SO much power that my 3.31's and 26" tall tires would be a piece a cake to turn over!!

pdq67

I was not going to go any higher than 9.5:1 but, AFR told me that recommended 10:1 or higher. How often do you adjust your valves with the solid cam?

I'm running the same AFR heads you have, on my 489 and I ended up with a Comp custom solid roller cam, 252/262 @.050 lift. .637/.623 lift. I dont know how much power you are looking to make, but those specs sound small for the kind of air those heads will move, not to mention 500 cubes.I'm not sure who you talked to at AFR, but talk to Tony. He designed those heads and knows what cams make the best power with them. graemlins/beers.gif
Steve

Why the split duration cam?? :confused:
I would think with the excellent I/E ratio of the AFR's, a single straight pattern cam would be better.
Just curious...I don't pretend to know more than Tony. :cool:

Bill, Tony didn't recommend my cam. I didn't know exactly which heads I would be using when I had the shortblock built. Fasttimes in Chicago built the short block and all i told them was i wanted a 600 hp 489" motor. So that is the cam they selected. I bought the heads from Mike (Wolfplace) and he said the same thing! It was also Mike who said Tony could recommend a good cam. building this motor has been a learning experience for sure and I hope the cam still works OK. Just wanted to compare specs with 396/375.
Steve

SMS, I talked to a fellow named Jason @ AFR! How streetable is your 489?

Well It's still on the stand waiting for pushrods right now so I really can't say! This is a brand new project that hasn't hit the streets yet. With the weather the way it is here, the car wont be moving till spring anyhow. I talked to Jason once about delivery, but you need to speak to Tony, He is the MAN :D

Hi,
I'll be heading to the dyno in the next week or so with my 498. I also have the AFR 305 heads with the CNC chambers. After grinding the tops of the bores to help unshroud the valves, and adding .051" head gaskets (my deck clearance was from .000 to +.007") we ended up at 9.4:1 CR.
I have a Scat rotating assy with SRP pistons.

I selected the Comp XR292R-R10 cam which is 254/260 .660/.666 110. No one helped pick this, it was my choice.
As far as the extra exh duration, on a car with a full exhaust it just might help. I agree that a single pattern cam is also a good choice.
I went with the XR series because it's an advancement over the older series. Again, my choice.
I will be testing 2 carb setups. A 950HP on a new World Products single plane, and a 1050 HP on an Edel Victor 454R.
Myself, I wouldn't use a hyd roller. The valve train is just too dang heavy. We put one of the XR hydro rollers in a friends rat and it floated the valves at 5800. It ran stronger with a 292H in it.
I'll be letting the group here know our results, so stay tuned.
Ron

You may or may not think this is crazy - but you should contact Mike (Wolfplace), have him get with you on a .600 Lift Isky Flat tappet hydraulic on the P55 Core. Isky has some flat tappet lobes that are huge. A couple months ago, when I was first looking into the 496, I was strongly considering this route. When I finally get back on track, I will resurrect this.

Give you an example:
H392/H584 292/298 244/252 .573/.573 112LSA/110ICL

H443/H393 296/306 248/258 .602/.629 114LSA/112ICL

Inexpensive but easy to run. The P55 core is a premium core, custom ground for about 180.00.

Worth considering.

Seems like WAY too small of a cam to me. I just can't think of any reason to not be over .600 actual valve lift on ANY big block head, stock or aftermarket. With heads like that that flow well into the near .700 range, you're leaving way too much on the table.

I also think your RPM range will be very low with a 230*ish cam in there.

I'm not a fan of hyd. anything unless it's in my pure daily driver back and forth to work car. No reason to mess with them in a street toy. If you stay out of the wild race cam stuff, the street rollers seldom need messing with.

I used the 244/244-.623/.623 on a 110 Comp street roller in a 427/Merlin oval port deal. It peaked HP at 5850 on chassis dyno, but hung in well to 7000 rpm..only dropped 6 RWHP. Great broad TQ range. Held 14" of vacuum etc. But I think that's pretty mild for a 496.

In my 540 I used a 262/273 on a 112 that peaked at 6200-6300 or so.It had fantastic midrange and was actually slightly crazy in the car with literally "light the tires up at 70 mph" type performance. I actually went to larger cams to kill off some midrange and get it to be more usable. Later a 272/278 on a 110 peaked at 7400 (after head porting and new intake). I now have a 266/272 on a 112 that is peaking around 6600 or so. Works perfect with 11.06 compression on pure pump gas.

I think you need to be out "at least" in the mid 250's area...even pushing 260 if you want to use a 112 LSA. Get lift in the mid .600's and be happy.

I know Tony always recommneds single pattern cams for his heads, but he will also tell you that they base that on open header development. Obviously using a street exhaust can change things a litte.....

You can get a much more serious cam than some of the Magnums and run great with longevity.

And if a solid roller scares you, I'd go to a nice solid flat tappet. I stuck a Crane 266/276 with .600/.620 on a 110 in my 540 for the heck of it once. Street manners were decent, but not as good as the much larger rollers, but frankly it ran VERY well. I was surprised it did as well as it did considering my heads would love .800 lift and it's an very old design. But I never touched the valves through the summer and it would pull 7000 rpm withno issues. Not as strong as big rollers, but definitely respectable.

You are also going to want to get past the 2.5" exhaust...it's going to need at least 3"+ to breathe. Not sure what headers you have, but most likely 2" ones will be perfect. I did some dyno testing on the 540 with 2", 2 1/8" and 2- 1/4". Up to 6000 or so the 2" were clearly better even on 540" and my big cam/heads/intake. Past that there was a 50 HP loss at 7000+ rpm though. The 2-1/8" are a nice compromise on 540's without N20.

Going to need more carb too. Need to be out in the 1000 cfm range at least even on a mild one. A buddy with a very mild 540 picked up 17 rwhp going from an 850 to a 1000 HP. And 30+ RWHP going from a dual plane to a Holley Strip Dominator single plane. Once you get out to these cube levels, you need airflow..I can't see choking it with a dual plane even if it is a great RPM Air Gap one. It will do OK, but I think a single plane would do better especially with stick trans. His streetabilty are even better he says these days...that's with a Tremec and 3.08's.


JIM

Gee????

Little old me thought we were talking about a nice MILD, big, street motor is all..

But please carry-on b/c I'm readin' anda learnin' right along too....

pdq67

Thanks for the info Jim! graemlins/thumbsup.gif
Notes taken...

I agree with 540HotRod.
Completely.
Especially on the cam,carb and exhaust.
Go for more cam, bigger carb and at least a 3" exhaust. The car will love you for it, and it won't be any less streetable.
No sense building a big cube motor and treating it like it's a 396.
Ron

I'm just learning about these bigger cubic inch motors but, with all of the bigger cams that were mentioned would I have any off idle power or would it be all upper RPM range. Just trying to gather info. Help!

Like Pdq67, I confused and puzzled at the suggestions as reading what AFR is suggesting considering CR, gears 396 has, I think a cam in the 570-to 590 lift range would be plenty for a reasonable street car! For the street a Holley 950HP would be perfect for a 496 with 10cr and cam that AFR suggested and 396 you would great throttle response from idle on up! I run Comp cams mid 600 lift in my race only car, idling at 1100rpm! Please go with professional suggestion and you will be much happier! ;)

If you use a cam that small, you may as well sell those AFR heads, bolt on a stock set and save yourself $2K+. While I may not be a "professional", I do know those heads are intended for much more than a .570 lift,245°@.05 hydraulic cam. Especially with CNC ports! Why not make the most of your $$ and get the right cam? If you spent the jack to buy these heads, you are obviously interested in making serious power. However, I am not a professional :rolleyes:

I would recomend an XR292R Cam.

650+ Hp under 6100rpm will be real fun. ;)

Well, as always it depends on your idea of streetability. If you want a 600 rpm idle that's one thing....but to me a 900-1000 rpm idle is not an issue for a street toy. But you have to realize that with that much stroke and that many cubes you need more everything to make it run in the rpm range you're used to with smaller stuff in smaller motor. A buddy just went through this with his 540..with a 236/240 hyd roller cam, GM/Edelbrock rectangular port heads, 10.5 compression he had a really great tow motor. Great low end tq but was dead after 5000 rpm. Peaked HP in the 4900 range. New cam 245/250 and head porting got it into the low 5300 or so peak HP range. He is now going to larger heads again and will change cam later to get it out there.

Low end will not be an issue. The 262/273 cam in my 540 would lug to 1000 rpm in high gear with 3.36's using 365 cc ports and a single plane intake with a Dominator.

You're in a whole new ballgame with cubes and stroke to play with. I hate driving a motor that runs out of air at it's peak hp. Think ZZ502....I hate the way it runs out of the box...it's dead after 5200 rpm or so. Great if it peaks at 6000 or so..but bad if it's a pig at 6300. You want to keep the powercurve hanging on as long as you can.

Way too many people buy into the TQ is everything deal...great for diesels. A better definition is proper TQ over the broadest operating range is everything. If the tires are spinning..you have enough...no need to make 700 ft lbs at 3000 rpm....better to have it come in higher and hang on longer. Car will be much faster and fun to drive.


But hey...I could be wrong........


JIM

I JUST TALKED TO TONY AT AFR, AND HE TOLD ME THAT HE WOULD USE A SOLID ROLLER WITH IN MY ENGINE! AROUND THE 250'S RANGE ON THE INTAKE AND HAVE A 4 TO 6 DEGREE SPLIT ON THE EXHAUST. ALL OF YOU GUYS THAT ARE RUNNING SOLID ROLLERS, SHOULD I BE AFRAID OF THEM, SO MANY PEOPLE WILL TRY TO TURN YOU AWAY FROM THEM. IS MOST OF THERE FEARS BASED ON 30 YEAR OLD TECHNOLOGY? HELP!!!!

if any of those CC rollers are ground on their "cast billet cores" I would do a little more research before spending the money. There have been some QC problems. dig around on the net a little, there's plenty of info out there. Have you looked at Isky, Crower, Crane?

Tom

If you stick with a solid roller (steel billet) that is not too crazy, like the one you mentioned, I think you should have no problems. Just don't skimp on the supporting components!Isky Red Zone or Crower roller lifters, good roller rockers and pushrods are a must. If you do go with a steel roller, don't forget a bronze dist. gear and a bronze tip fuel pump pushrod.Some steel rollers have a cast iron gear so you have to check. A solid roller set-up will cost a few bucks, that you can count on.
Steve

Tom
Elaborate on the CC reliability problems with the cast billet core.
I have one ready to hit the dyno. I also have friends with many miles on them w/o problems.
Ron (XR292R)

I have the xr286r on a billet core with a cast iron dist. gear, cost almost 300.00 and its ground on a 107 lsa instead of the 110 lsa, this thing is a little noisy but man its got guts, can't wait to get it to the track :D

We use a single pattern UD hyd roller in our 534"
same basic motor as you but with a touch more bore and Dart 325`s.

Anyway, 255 @.050 .650 lift. 110 sep. Shifts points: 1-2 @ 5600-5800, 2-3 @ 6000 RPM.
6400-6500 rpm with 3.73 gears @ 130+ at the end.
10.19 ET..

Somewhere there abouts cam wise and you will be good to go, call UD Harold @ Lunati graemlins/thumbsup.gif

Everybody will have their preferences as to what would work best, but I'd have to agree with 540hotrod and Ron454. With those heads, it would be a shame not to step up to a solid lifter or roller with more lift and duration. I went striaght to a 112 solid roller with 250/250 @ 0.05,.705/.702. These values are after taking lash into account. This is on a 509 with AFR 315 heads, Should keep the power brakes happy and meet emission requirements ( have to pass the sniffer, but no visual).

With your long arm 496, you shouldn't have to worry about off idle torque or power. I'd be more concerned about getting the torque to the ground.

John

Cam selection is always interesting stuff. Most recommend a large 250-270@.050 cam, which certainly will make the big power, but the more aggressive the cam, the harder it is on valvetrain and generally hurts the vacuum.

I recall the Red Line Oil 540 that had a 244/252 Crane solid roller with ported Merlin Grumpy Jenkins heads (estimated 325 cc), and a single plane intake. It made peak power at 6100 rpm. But mind you this cam had 294/302 advertised duration.

You'd think a 254/260 cam would peak way up there on a 496.

The 255/263 UD solid peaked at about 6500 im my 454 on the dyno. So I think a 254/260 roller will be less in a 496, I'm guessing around 6000 to 6300?
We will soon know for sure.
Ron

Was that with the AFR 305s? Also what intake and headers were on the 454 when it was on the dyno?

A few of my thoughts on your deal :D

The 254/260 will not "peak way up there" in a 496 especially with the dual plane intake.
It will peak about 6000-6300 & make peak torque about 45-4700.
And listen to Tony,,,, he designed the heads & they love lift.
You do not want a baby cam in a 500 inch engine, they like cam smile.gif
Also, do not get caught up in the DCR deal with big engines, they make torque with a lot more cam then the numbers suggest.
On the roller, I would not use a cast core for a solid roller, you cannot put a real spring on them.
I personally hate cast solid rollers :(
Have it done on a billet with the cast gear option.
Do not skimp on lifters. Use Red Zones or Crowers, my preference is the Isky's.

If I were doing your engine I would recommend the Weiand Stealth as it has bigger runners for a dual plane but I would prefer a Vic jr with 500 inches unless you are towing a house behind you . :D
A Vic jr single plane will make over 500lbs ft on an honest dyno at about 2800RPM with those heads & more power above 6000.
Also, you are correct the carb is way too small, especially with a dual plane ;)

If you decide on a roller, email me & I can probably save you a few dollars on the Isky lifters.

I have olny slightly stronger springs than Comp recommends.
What fails on these cast roller cams?
You have seen this fist hand?
Now I'm freaking out.
BTW, can't find any horror stories on line.
Ron

Actually, I spoke with Comp about this dilema, and they will swap me cams and give me a billet cam with a pressed on cast iron gear for a very reasonable fee.
I believe I will do this.
They were very friendly.
Also said that as long as I am under 450lbs open, no problem even if the seat pressure is 200lbs.
Ron

What would be the down fall of over.700 lift in my 496 and 305 AFR's with .252I/.260E. Also, how often would one be adjusting valves with the solid roller?

Originally posted by Ron454:
Actually, I spoke with Comp about this dilema, and they will swap me cams and give me a billet cam with a pressed on cast iron gear for a very reasonable fee.
I believe I will do this.
They were very friendly.
Also said that as long as I am under 450lbs open, no problem even if the seat pressure is 200lbs.
Ron =
In my politest & most respectful terms :D ,,, in my opinion they are full of crap regarding spring pressure but I am glad to hear they are willing to do you right.
I have a couple of first hand units, one is an XE series HR small block with 357 on the nose & a rev kit that was 90lbs.
This is quite a bit less than 450 at the valve.
It was showing signs of tracking in less than 2000 miles.
It was taken out for another problem regarding the distributor gear but this is the second cam I have seen with excessive wear on cast core cams with around 450 open pressures.
The other was a rat which is worse because of rocker ratio.
You have a lot more pressure on the cam with a 1.7 rocker than a 1.5 rocker.
I will not use a cast core cam for a solid roller & prefer a billet for any roller ;)

Just to be fair, I know of a few cast HR's in small blocks that have about 425-450 or so spring's & have been running around for a number of miles & years now without any apparent problems so it may not be a problem in all cases ;)

Ron,

I am going to send you a pic in email of what happens to cast roller with too much spring pressure. You are free to post it on here for all to see if you are so inclined.

Thanks Joe and Mike.
We will be removing the non billet cam and replacing it with a billet core. I'm not going to sacrifice all the $$$$ I have in this pig due to cam failure.
Too bad I have springs and pushrods, or I'd pick a bigger cam.
As I told Joe, Comp has changed their spring recommendations since I bought the cam......to springs with a much lower open pressure. (on their website) And I KNOW I didn't look up the wrong ones initially.......
Sometimes...crate engines sound better and bettr all the time.
Ron

Darn!!

I would love to see somebody use one of the Schbeck "radius foot lifter" solid cams or their new "axle-less roller lifter" cams spec'ed like we are talking about in a 496 or 540 motor just to see what would happen!!

AND I'm talking about a 25,000 mile long term street AND track driving test here guys so we will know for sure aboutr any longevity issues that may crop up!!

Be worth the price of the mag issue if they would spring for the test to me..

Hope some of the mag. people are peaking in?????

pdq67

On a similar note about cast iron rollers, ask anyone who is into turbo buicks about the Comp Cams cast iron roller cam fiasco a few years back. They won't even discuss it! Many guys lost their engines to those POS cams. Supposedly they have a new type that wont disintegrate now.