Thread: Cam Selection, have specs.

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Got the heads from a local machine shop where they were machined with the springs and guideplates preinstalled.

I know, I've learned my lesson on overcamming on friends cars, and on one of my own projects. I'm not brainwashed with the 'bigger is better' way of thinking. Got that much

-Rob

.....I ran your combo in my Desk Top Dyno; 350, Dart 180 Iron Eagles 2.02 & 1.6's 72cc, 1.5 rockers, to get your compression ratio I used; flat top pistons, 0 valve releaf volume, .040 head gaskets, .075 quench, 72cc heads & came up w/ around a 8:5 to 1 compression. 600 carb w/ a high torque dual plane manafold, small headers w/ mufflers. And 5 different cams all of them the Comp Cams Xtreme Energy, Hyd Flat Tappet.

1. XE-250H, #12-230-2, duration 206/212 @ 1/2", .432/.444 lift. It put out 413 Tq @ 3500 & 346 Hp @ 5200.....

2. XE-256H, #12-234-2, duration 212/218 @ 1/2", .447/.454 lift. This put out 411 @ 3500 & 363 Hp @ 5500.....

3. XE-262H, #12-238-2, duration 218/224 @ 1/2", .462/.469 lift. Put out 412 Tq @ 4000 & 373 Hp @ 5500....

4. & 5. Cam #4 that I ran was the largest that was recommended for a stock converter but a 2000 stall was suggested {not sure WHAT the difference is between 'recommended' & 'suggested'???}.... Anyway this cam did 406 Tq @ 4000 & 384 Hp @5500. BUT the TQ was only 355 @ 2000 where as the first 3 cams were; 389, 379 & 371 @ 2000.... I would not use #4 because of this. Cam # 5 was just plain old 'way to big'.....

I also would not use #1 as it fell on it's face between 4500 & 5000. I'd go with # 2 but #3 would work.

THIS IS JUST MY OPINION THOUGH!!!

It's not that I'm all that knowledgeable, I just have a Desk Top Dyno!!!! Call Comp Cams and ask them & let me know what they advise. I called them a couple of weeks ago for a recommendation & went one size smaller...... hope this helps ya, Bill

First off, let me say this:
Bill, thanks for your time so far, I really appreciate it. I too have been running some different cam options through Desktop Dyno and getting similar results. When you say 1/2", you mean fifty-thousandths (.050"), right?

I called Comp Cams, and a hurried-sounding tech advisor half-listened to the specifications I painstakingly prepared for him and spit out:
"Yea, yea. Uhh, why don't you go with the 12-238-2. Should be fine."
"Alright. Will the provide a decent idle, and good street power for my application?"
"Uh huh."
"Great." *click*

Looking into this cam, it's specs are:
Duration: 218* int / 224* exh
lift: .462" int / .469" exh
110* LSA

Desktop Dyno says that it will be worth 382 Fly HP at 5,500RPM.
Somehow I don't buy that
I am gonna look into your specs a little, and see if one of these will work better for my application, thanks again for digging these up.

Cam Breakin Question!
Comp cams specifies that for a double spring application, to remove the inner spring during break in. Like it's as simple as yanking out a spark plug.

Does this mean I have to break in the cam, pull the valvetrain apart, install the inner springs, and pop for new seals, doing all of this with the motor in the car for break-in purposes? Jeez, what a headache!

I guess a 70' Nova is out of warranty though
-Rob

...hey Rob, yes by 1/2" I meant .050 {when I type I know where the all the keys are to type 1/2" w/o looking. To find the '5' & the '0' keys I have to look, so it's easier.....}. Ok, so you have a Desk Top Dyno also. I just got mine a couple of weeks ago. There fun to play with, huh??? Anyway, it looks like Comp Cams recommended the #3 cam that I mentioned. When I called I talked to Matt he was great on the phone. In fact, since Summit, Jeg's and SD Chev were all out of the cam I wanted, I just ordered it right from Comp. {I called Comp 3 times & one of those times the guy I talked to was sort of 'in a hurry', may be it was break time??? But once I talked to Matt I just asked for him everytime. So you might ask for him if/when you call back}. Oh I got a 4/7 cam which reverses the number 4 & 7 in firing order sequence. They say it gives you a flatter Tq curve & the engine runs smoother & cooler. They can grind this on any cam. I saw where Comp also has a 'Cam pick' program that's available for $35 bucks. I thought about getting it but then I had to do something quick as the guy is already working on my motor.
LOL @ '70 Nova is out of warrentee! .;.... In fact I bought a '69 Nova that had the FULL factory warreentee once. Now that's good & bad. The good part was the warreenttee {although it & the car are l-o-n-g gone}. The bad part is that you've got to be in your 50's to have done this ...
All I know about break in is Comp told me to have my engine builder pull the 2nd spring for break in. In fact do I EVEN have 2 springs per valve??? I'd better go ask some 'valve spring' questions..... But I belive pulling the spring is only for the Extreem Energy cams.
Yes I also wonder about what the Desk Top has said my motor will put out. I HOPE it's right! They say it's to within 5% +/-.... Plus would be nice, huh???
And just remember to think TORQUE! more than hp..... Look at the Tq. @ 2000, 2500, 3000, 4000, 4500, 5000 RPM's. The largest cam that I ran for you put out 384 Hp @ 5500 but only 340 Ft. Lb's of TQ. @ 2000. The smallest cam only put out 346 Hp @ 5000 but it did 389 Ft. Lb's at 2000. Torque is what will make your car fast on the street ESPECIALLY with a stock converter......
have a good week end Bill

Well, like they say,
Horsepower is how fast you hit the wall,
Torque is how far you take it with you.

Anyways, I think I'll go with the #2 cam, nice torque curve to match the horsepower.

I'll let you all know how it goes just as soon as I start her up.

Any other ideas for the valvespring removal would be cool also

Thanks again,
-Rob

Originally Posted by SBC Maro

Well, like they say,
Horsepower is how fast you hit the wall,
Torque is how far you take it with you.

Anyways, I think I'll go with the #2 cam, nice torque curve to match the horsepower.

I'll let you all know how it goes just as soon as I start her up.

Any other ideas for the valvespring removal would be cool also

Thanks again,
-Rob

.....good quote, how far you take the wall with you.... Yeah, #2 is a good choice. I know I went one under what Comp recommended to me. I DON'T want to have to buy another Tq converter! Yeah, I'll ask my engine guy r/e about the valvespring removal. I'm sure he's not going to be to happy. He recommened AGAINST me using the Comp Xtreem Energy cam & I thing THIS is why! He probably already knew r/e the spring thing....... Hey your in Lompoc, were're neighbors. I'm in Ojai, Ventura County....
Bill

Yummy! Lompoc=Anderson's. Best pea soup on the planet. Anderson boys used to run a flathead rail. Wasn't as good as the food, though.

Oldman2