Put up some more vid's of it in action.

 

Looks like I have one of the smallest cams in my 383

Comp cams XE 270

270/276
218/224 @.50
.495/.502 w/ 1.5
110 lobe

this is with 10.5 CR

Next one will be MUCH bigger.

 

I see i good amount of people runnin the xfi lobes 230-236 mid-high .500lift 112 cam in the 383s that make great all around power for street and strip!

 

comp cam XFI 280 230/236 412rwhp

 

What heads/springs do you run? At what rpm? Nice numbers

 

BINGO

 

So; what CAM would be optimal for a highway/street driven 383 that will rarely see the track?

 

What intake / trans / gears?
Other mods ?

 

It all depends on the intake you choose,gears, etc, on my motor Im running a ported high flow TPI setup that won't see over 5400 rpms on the street, so my 218/226 cam is a good match. If you have a miniram that all changes, the rpms can go higher calling for a cam that will handle into the higher range. You always need to match engine components... WW

 

Holly Stealth Ram, ZF 6 Speed, and stock 3.43 gears. Plus long tube header, True Dual's (no cat), 52mm TB, 32# injectors, and AFR Eliminator 195 head.

 

Comp Cams custom grind...

230/236
.622/.624
113* LSA

411rwhp on a Mustang dyno which is ~450rwhp on a Dynojet dyno

Pretty benign idle

 

Any problems controlling those lobes? I was thinking of trying a 242 or 244 duration .640 hydraulic roller cam from comp but I'm afraid thats going to be hard to control especially in a boost motor with a big valve. Almost need a light solid roller spring to handle it

 

 

Nope, no issues Lots of road course time at >6000rpm

 

OTOH, you should realize that whatever cam is chosen for the setup listed, the final HP numbers aren't going to vary much more than 20-25hp. With a SR cam (219 duration), I would predict 390rwhp. As you've seen 230 duration cams are hitting just above 410rwhp. There are other little things that can affect the outcome but this should give you (the OP) an idea what you're choosing from.

The final choice within the range of 218ish to 236ish should be based on where you plan on spending most of you time. For a street car, lower rpms see way more action. Getting an acceptable vs good idle may be a goal. With AFR195's even the smallest cam will launch you near 6200rpms. On the opposite side, their port velocity will provide a fairly tame idle with a bigger cam.

It's really hard to go wrong, but unless you're going for all-out 1/4 mile times, I think a smaller cam would be more street friendly. I say that because, whatever cam is chosen won't idle like a C6 factory car. But, a smaller cam will get closer and provide more off-idle throttle response -- something that's not exact NEEDED with the torque of a 383. It's still nice to have though.

 

One thing that shouldn't be forgotten is when dealing with the leaders in the camshaft/valve train industry, their camshaft offerings have been extensively tested in various different ways. This is done to determine what'll work and what won't. Now, I'm referring to the leaders in the industry, of which there are really only two or three that qualify.

This testing also includes what springs have been shown to work with a specific cam profile, what alloys the springs are made from, pre and post winding tests, their pressures and the RPM operating range, etc. So identifying the correct springs has already been done by their engineers - not some guy sitting at the Customer Service console. In many cases there may be more than one part that fits the bill, but usually one is identified as the preferred or premium choice.

It's when guys deviate from the tested and recommended parts that the problems creep in. Running springs, retainers, locks, pushrods, etc., that have NOT been tested and approved to properly operate with a specific cam causes many of the problems.

As an example, one set of "middleman recommended" springs wouldn't fit because of the interference of the damper/valve stem seal. So the buyer was told "Oh, just remove the damper". Now that's CRAZY! Obviously the engineer who designed and tested the spring determined the need for the damper, but since they didn't fit the head with the damper installed, buyer was told by the seller to just remove the damper. There goes all that engineering effort out the window. Try to be smart. What will be the result of doing that? It's NOT the way to properly build an engine and introduces unknown variables.

Guys do that parts swapping for a few reasons, like trying to save a few $$; relying on the recommendation of some other guy - even someone who is otherwise well respected. I've read a couple of cam tech engineers say during interviews "Never let your friends pick your cam". I'd add ESPECIALLY critical parts, like valve train parts.

We don't have the million dollar computerized equipment the BIG companies have nor the expertise to test, and more importantly, the ability to understand what's REALLY going on as the RPMs climb. Common sense should dictate that all that testing be left to those who have access to the required equipment and have the necessary training.

My position and contrary to what so many seem to believe, (that off the shelf cams are not as good as a "custom"grind") is flat out wrong! Why? Because of the shelf grinds have all gone through ALL the testing and have shown the profile to meet the company's high standards. In addition they have the science to back it up. The term "Off The Shelf Grind" is NOT a negative title; "Custom Grind" IS.

Somehow this "custom grind" blitz has started to get out hand. Seems guys just LOVE to throw around that term as if it makes his cam choice BETTER than an Off The Shelf grind. Sellers/recommenders claiming to know about a "better" way of grinding a cam or knows of a "better" spring, etc., is, to me, so much BULL. Ask them to provide the science backing up their claim, not what so and so did when he used it - Far too many variables involved in that kind of recommendation.

This valve train business is very competitive and you won't find one company telling you that another company's products are better than theirs. They all tout their stuff as being the best; yet where's the science to prove it? It's mostly salesmanship with the middleman probably having cut some kind of business deal with the supplier.

This is where doing your homework comes into play. LEARN TO LOVE TO READ. Find out which products the consistent winners use. Be objective but don't get cynical. Cynicism causes many to attribute the use of a certain product to the product manufacturer paying the user to run it. That's STUPID.

With the multi-million dollar sponsorships NASCAR and PRO STOCK teams have they can choose what ever parts they want and since those two forms of racing (just to name two) are so competitive it wouldn't pay to use less than the best parts available. To do that would result in less than desirable wins/places that would have a direct impact on sponsorship. You've got to be 'up top' and stay there in order to keep that sponsorship money rolling in.

This may be the first time many of you have read anything similar to my "custom grind" objections (I know I haven't before), so I expect disagreement and a lot of that "So and so did such and such" kind of responses. These are just mine; you're welcome to yours.

Jake

 

I disagree. Even custom grinds have been tested if they are selecting from their own proprietary lobe catalog. Most will have access to spintrons and do lots of testing. But a custom spec'd cam will also be better than the off the shelf grind unless you happen to build a motor that fits the valve events of an off the shelf grind. Shelf cams are made to be a so-so fit for a variety of applications while a good custom grind is spec'd for your exact combination of parts and rpm range.

Shelf cams will be used in a variety of motors with different valve sizes/stroke lengths/rod lengths etc and cant account for the exact piston motion and air flow demand. They are designed to mix OK in most engines but will not give best performance over a cam designed for that application. Unless you built a motor that actually required the same valve events as the shelf cam came with.

And a cam's advertised ranges and spring recommendations are not always accurate. Case in point, comp cams. Alot of their aggressive lobe xfi stuff is capped off at 6200 rpm as the operating range... meanwhile the 292 cam will pull to near 7000 rpm on the right 355 motor...if you can control the lobes with the right spring pressure. They recommend the 26918 beehives but I dont think they will be enough. I'd run the Pac springs beehives with 150lbs seat compared to the measly 125lbs seat pressure. I seen those 918 beehives fail to control the 268xfi cam above 6000 after they lost spring pressure due to heat cycling after a year or so of operation.

 

I am going "Custom Grind" as you sayto get the fattest curve I can for Roadracing. Im sure there is a shelf cam that would work but not maximize the potential.

I dont know if he is on here but Patrick G from Texas specs cams out for people everywhere. He is VERY well known. He uses the head, intake, and application to decide what would be best. There is no off the shelf cam that does this. If there was the shelf would have MILLIONS of cams.

 

That's probably the main point of consideration/contention that may come out of this thread. If you select existing lobes to create a different split, the risk is minimal of doing something "wrong". Some of the new heads are flowing so well that people might consider running less/no split to gain a bit of torque. That's just an example.

If you pick an off-the-shelf cam, you are just as likely to have some power left on the table, have too aggressive an idle, or some other scenario that's less than "ideal". For any given combination of parts and application, there is an exact cam out there that will create optimum performance. Odds are it's not necessarily one of the shelf. OTOH, when you're talking about an outcome of a couple percent away from the best power you can get, or best idle, or best mpg, or whatever,,,,you can get pretty darn close with an off-the-shelf cam. For crying out loud, have you seen how many lobes there are to choose from? More importantly, most cam manufactures will combine any two lobes you want to use. Ask yourself,,,will you be upset if you only hit 390 vs 410rwhp? If not, don't fret the agony of a custom cam. If so, pay someone who optimizes cams or invest in a good simulation program like EA Pro. You won't be that far off.

A good point is being made about lobe designs themselves. While something like the newer XFI lobes are supposed to be better engineered to help the lifter stay on the lobe, I think a lot of setups are designed specifically for making the best power during the course of one or two seasons. (After that, maybe you'll need new springs for example.) When you get into long-term reliability you have to start asking more questions and/or add more elements for longevity. Even then, power is something that's got a give and take element to it. To get that extra power, you'll probably be giving something up to gain extra power.

Edit: There's a couple of easy things I learned while building my motor that may be worth sharing. Everyone knows you only get about 10hp for every 10 degrees of duration. I'm not as sure about lift, but it probably on the order of 10hp for every .030" lift (assuming the heads flow well for the extra lift). On the more practical side, use more duration when the intake or exhaust doesn't flow as well. Use less if it does. That's why (for example) that the AFRs don't need as much exhaust duration. It's why a short runner, free-breathing intake might not need as much either. It's why a long-tube intake might need more.

Also, despite what some people say about bigger cams having good manners and being streetable, don't expect a performance cam to idle like stock. I've got one of the smaller cams you'll see (SR-like cam). Another friend has the easy ramped Hotcam. You can tell they both have cams just by their FEEL at idle. That's not always gonna be enjoyable at every stoplight/sign. I'm sure some days, I'll wish it idled as smooth as stock. I don't think this is a "Buick mentality" either. It's just common sense. Kinda the same thing as getting tired of exhaust drone, or a stiff suspension, or a bouncy suspension, or Repulicans, or Democrats. They all get on your nerves after awhile!

BTW: I probably won't get tired of the extra power though!

 

Gregg , you got that right....Lovin my 383, I will never go back to a 350...WW