mud

I'm trying to decide on a cam and need some enlightenment about cams.

My sig lists most of the details on what I'm working with, but here is the rest of the info:
I'll be running an x-pipe with 3" duals/dumps. EFI Controls will be FAST wideband, Holley w/wideband, or DFI gen 7.

Also, here's the specs on my heads:
------ I --- E
.050- 30 --- 23
.100- 63 --- 50
.200- 123 -- 102
.300- 177 -- 138
.400- 220 -- 171
.500- 252 -- 188
.600- 257 -- 197
E/I -------- 78%

As you can see in my sig, I've used quality parts throughout the valvetrain and my springs can easily handle any of those cams.
I don't have them yet, but I'm getting some 875-16 Comp R" series magnum lifters.
I don't plan on using a rev kit, but if the need arrives I'll add one later.


The car is built soley for STREET RACING. Only once in a blue moon I may go to the 1/8 mile track and if so I'll run drag radials at best. I'm gonna be using N2O but only as insurance. Even though it's not a daily driver, I'll be cruising around from time to time so I do need to retain some degree of driveability. I don't mind making some sacrifices. I don't have AC or smog anymore, and I'll add a vacuum can or pump for the power brakes if needed. Plus being having a manual tranny and using some type of dfi system should make it more tolerant....correct me if I'm wrong.

COMP recommends their XE 282HR custom ground on a 112:
230/236 282/288 .517/.527 w/1.52's or .544/.555 w/1.6's 112*
But I've also had my eye on this one:
236/242 288/294 .527/.547 w/1,52's or .555/.576 w/1.6's 112*

OR
Crane makes a couple from their powermax series that's also sold under the GM Performance Parts Name.
Crane 109831 / GM 12370846
222/230 284/292 .516/.535 w/1.52's or .543/.563 w/1.6's 112*
Crane 109841 / GM 12370847
234/242 296/304 .546/.565 w/1.52's or .575/.601 w/1.6's 112*

It's my understanding that the 112 broadens things out a bit and will complement nitrous. I should still have a pretty good sound from the 112 while being a little easer to tune the efi.

Would it be better to switch from 1.6's to 1.52's?
My heads have guideplates, so I'm thinking about switching to the traditional style instead of the self-aligning anyways.

How do these cams compare in relards to my application?
Please, be as technical as you like. I'm trying to learn from this instead of asking someone to pick me a cam.

Any alternative or custom recommendations?

F-BIRD'88

looks like either of your choices would be good.

I like the Crane hydraulic roller systems myself.
If you're using a Vortec block you should be able to use factory
hyd roller lifters and save money.
Other wise crane claims to have a superior retro fit hyd roller lifter.

Consider using a "rev kit". Really helps at high rpm as your limited
on how much pressure a hyd lifter will withstand and still operate properly. the rev kit does not alter the pressure as seen by the lifters' hydraulics.

mud

F-B88: My valvetrain is almost complete, and is nearly bullet proof for my application.
Rollmaster billet timing chain
4130 one piece 3/8's hardened pushrods
Competition Products/Howards Cams 98213 springs and ti retainers (same size but a little better rate than Comp 941's, plus better material and manufacturing than comp's)
Comp Pro-Mags 1.6 self aligning
I don't have them yet, but I'm getting some 875-16 Comp R" series magnum lifters. They use the factory hardware.
I don't plan on using a rev kit, but I am going to try some of the new composite LS1 style lifter retainers that GM Racing now offers. It eliminates the need for special lifters for high lift applications.
If the need arrives, I'll add a rev kit later.

Basically the cam is my only variable I have left to solve.

Where's vader, or willie, or rb83l69, or madmax, or some of the other guys who really understand camshaft/valvetrain dynamics?

I've tried the search but I can't find anything that relates.

RB83L69

Unfortunately comp and Crane rate their "advertised" duration differently; Comp uses .006" tappet lift, Crane uses some lower number. So Crane's cams tend to look on paper like they have less aggressive ramps.

With that really low compression and FI, you need to keep the intake duration relatively low. But of course you want all the lift you can get.

Look at something like Comp's 3119 intake lobe and 3122 exhaust lobe. That would give you 224°/236° @ .050", .560"/.608" peak lift with 1.6 rockers. 112° LS would be OK. Crane, Ultradyne & Lunati could probably provide a comparable product. You'd probably want 1.55" valve springs for a cam like that.

mud

Isn't "aggressive" fast ramp rates the big new trend in cam grinds?
I don't know much about ultradyne.
I've heard some bad things about lunati.
Crane makes GM's performance cams.
Comp makes good things except some recent batches of valvesprings. They're the most "hyped".

Dang! That is some major lift though. My heads are good but not that good. And don't you think I could get away with a tad more duration than the usual efi car since I'm using a single plane and I'm upgrading to a wideband tuneable management system. M6 cars can usually get away with more as well..or manual tranny cars in general I mean.
This is good stuff though RB. Others please. This is what I'm looking for.

mud

ttt

Sitting Bull

F-Bird'88 knows his stuff. Don't insult him by asking for Vader or RB83L69 instead. Those guys know their stuff, too, but they will simply reiterate F-Bird'88's recommendations.

mud

Sitting Bull... You either missed the point of my post, or you're trying to stir up ****. I respect fb-88 and his replies. Hell, he and rb are usually the only ones who reply to my posts. He was suggesting a rev kit which is a good call, but I want to hold that off until later.
I'm looking for cam advice and as much tech info relating to the dynamics of these cams I listed. He didn't say much about them other than they looked like good choices, so I asked for some other guys input on it. Don't take it so personal man, It sounds like you're upset I didn't throw your name out there. Would you like to add something constructive to this topic? What is your take on the cams? How do ramp rates compare to each other?
Now back to the topic at hand.....

EDDIETA_ZZ3

I like comp cam products. Works well in my ZZ3
My roller 304 cam .500 / .510 114 LSA

Their .540 lift XE roller cams ought to be a perfect combo with those Vortec style heads

Sitting Bull

No, I don't know as much about it as those guys do. Out of my league

It seemd to me that you were saying F-Bird'88's advice wasn't worthwhile. Guess I was wrong, eh?

mud

Yes, I am not the best with words, so if it was misleading.....my bad. I like fb88, he contributes to my topics, isntead of post whoring like many do. His input is always welcome. Anyone who wants to add something that allows me to think about things I haven't considered is always welcome and appeciated. I try to use this board to learn.........and hopefully I've been able to shed some light on some things at times or at least give some food for thought over the past 5 or 6 years I've been here.
db

Sitting Bull

mud,

You and I will get along just fine now that we know where we're coming from

mud

Well.....I talked to Bret Bauer and he recommended something that should work good with the t56. Comp custom grind 224/236 .560/.544 w/1.6 112+2
He said that without a rev kit I should be able to shift it at 6-6200 no prob and then if I go to a rev kit, I should be able to get 6500 out of it and it'll really sing!

I think that's the route I'm gonna take.

jimmy_mac

For a long time during the 80s and even well into the 90s all the magazines where doing tons of cam articles. And with the roller cams coming on in the late 80s almost every month had an article on proper cam selection and how the ramps of the roller cams where so superior to flat tappets. And they are probably right.

Bottom line is, if you can afford a roller cam you will get a cam that opens your valves up towards its maximum lift quicker that the flat tappet. So for the same duration the motor will have more access to the higer lift cfm of the heads. And your heads flow well at higher lifts.

But as far as manufactuers go, from the profiles I have seen, the rollers are very similiar to one another.

I have the cam right below yours. The xr270hr. It just barely has a noticeable idle and pulls hard to 5500. Actually I have reved it past that before with it still feeling like it was pulling, but I prefer to shift there.

Oh, I noticed you said you where thinking about using new rockers instead of the self aligning with your guide plates. You have probably already figured this out, but, don't use the self aligning rockers with the guide plates.