[9K-sbc]

Hello, I'm recently running a Chet Herbert CR300 cam and was wondering if anyone else has run this cam. It's so radical that there's virtually nothing but popping and growling up to 5,000 rpm and then it pulls hard to 8,800 rpm. Then again, if you run this cam you already know that it's range is from 4,800-8,800. I would like to know if anyone else has used this cam and how it behaved for them.

Thanks,
Robert

 

[k-star]

cam

Can you post all the numbers form the cam please. Most of the guys don't have the spare time to look it up, but would be more then willing to help if they could just see the numbers.


Keith

 

[9K-sbc]

I'll try and post the specs later when I get home, It's got durations @ 050 of 283/296 and that's with 1.5 rockers and I'm running 1.65's. Advertised duration is 316/333. I've talked to Herbert cams on the phone and they agree it's all or nothing when it comes to throttle position.
I'm trying to find out if anyone has run this cam to compare behaviors.

Thanks,
Robert

 

[9K-sbc]

Ok here's the specs on the cam, HERCCR300
adv. duration 316/333
@ 050 283/296
lift 630/651
lobe center 108
valve lash .022-.024
center line 104
@ 050 int. open 37 close 66
exh. open 74 close 42
solid roller, 1.6 int. rocker, 1.65 exh. rocker, operating range 4,600-8,800 rpm,

It runs 6.50 1/8m shifting at 7,200 and will turn 8,500+ but I rarely take it over 8,000.

Robert

 

[techinspector1]

I've talked to Herbert cams on the phone and they agree it's all or nothing when it comes to throttle position.

Robert, with all due respect, if the techs at Herbert told you it is what it is, then IT IS WHAT IT IS. Don't expect anyone on this board to try to second guess the manufacturer's information. That would be foolish.

 

[9K-sbc]

Thanks for the reply, I just noticed that I have a header tube that's running cold at idle and this could be causing the "under 4500 rpm" issues. You sure can't tell that anything is wrong at higher rpm's,

I made another post about it a few minutes ago, I'm new to the forum thing so forgive me if I'm doing this the wrong way.

Thanks,
Robert

 

[9K-sbc]

"Don't expect anyone on this board to try to second guess the manufacturer's information. That would be foolish."

techinspector1, with all due respect, I didn't expect anyone on this board to do anything, My original post was "Is anyone running this cam?" not "what's wrong with my setup?" Someone said

"Most of the guys don't have the spare time to look it up, but would be more then willing to help if they could just see the numbers."

Again how does "anyone run this cam" turn into "please take the time to look up this cam and help me" please don't take my comments personally as I am just trying to see if anyone runs this cam. I appreciate any and all help that is to be offered on this board, and now I've probably gone and screwed that up. I guess I shouldn't have given any symptoms or posted specs, just stuck with "anyone use this cam". Again, no dis-respect intended, just a little confused with the replies.

Thanks,
Robert

 

[techinspector1]

Robert, you haven't done anything wrong. You're doin' fine.

It's just that you've plunked yourself down in the middle of a bunch of gearheads who have a propensity to over-analyze everything, me included.

 

[9K-sbc]

It's just that you've plunked yourself down in the middle of a bunch of gearheads who have a propensity to over-analyze everything,

Actually, that signs like a good place to be, I've read some of your replies.

It's been 30 years since I've raced and I'm looking forward to getting some advice from guys like youself.

Thanks,
Robert

 

[ericnova72]

What size engine, what weight vehicle, and if its good to 8800 rpm why are you only taking it to 7200 rpm?? The 1.6-1.65 rockers just increase the lack of low end, if you aren't going to rev it to 9000 rpm why did you buy this cam and put bigger rockers on it?? Was it a case of "bottom of the page" syndrome??

Are you running at least 5500 stall?? Better would be 6000-6200 rpm or more.

I've run similar size Comp 282/288° @ .050" .630" lift with 1.6 rockers and it didn't like running below 5200-5300 rpm in a 406 SBC.

I don't think you will ever be happy with it if you don't raise the shift point 1400+ rpm.

 

[9K-sbc]

Thanks for the reply, I was looking for some used brodix heads and ended up buying the whole thing. It's a 355 13.5:1, forged rotating assembly, brodix track 1's, and previously mentioned valve train with stud girdles. I agree it's built for 9000 rpm, It is in a 3000 lb car with 4500 stall and no transbrake,

Yah I know! that's why they had to use a 125 shot just to get it off the line. I'm looking into changing to a herbert CC6E which is a 3500-8000 range cam @.050 264/276 duration. Thanks for the info on your cam, that's what I needed to know, It's really rough down low and now I notice a cold header on #2 until it revs up so I have to look into that, I didn't notice it until today. Could you accelerate slowly up to 4000 or 5000 rpm? or did you have to stab at it to get the rpm's up.

Thanks,
Robert

 

[ericnova72]

Thanks for the reply, I was looking for some used brodix heads and ended up buying the whole thing. It's a 355 13.5:1, forged rotating assembly, brodix track 1's, and previously mentioned valve train with stud girdles. I agree it's built for 9000 rpm, It is in a 3000 lb car with 4500 stall and no transbrake,

Yah I know! that's why they had to use a 125 shot just to get it off the line. I'm looking into changing to a herbert CC6E which is a 3500-8000 range cam @.050 264/276 duration. Thanks for the info on your cam, that's what I needed to know, It's really rough down low and now I notice a cold header on #2 until it revs up so I have to look into that, I didn't notice it until today. Could you accelerate slowly up to 4000 or 5000 rpm? or did you have to stab at it to get the rpm's up.

Thanks,
Robert

It would take moving the throttle either way, that is mostly just accelerator pump and carb settings, but it wouldn't get off the line without A LOT of stall. I still have the Comp cam, it's in the box for the Herbert CC6E(jinx!) that replaced it, and we like the 6E a lot better, running it with a 1.6 intake/1.5 exhaust rocker. The 6E is still going to be a awfully big cam in a little 355 though.

The 4500 stall you have will still be a little low if you are using a Glide, not so bad if you are using a TH-350 or 400. Our experience is with bigger 383 and 406 engines, you might look at the 6F with your rockers, running the 1.65 on the intake side instead of the exhaust, nobody really needs a ton of lift on the exhaust side with a good head. It might be a better fit to you smaller 355.

 

[9K-sbc]

Thanks for the info, I looked up the 6F and it looks good. The reason I mentioned the 6E is because they had two on the shelf and I thought I was in a hurry but now I'm not because of the "dead hole at idle" issue that I noticed yesterday.

Thanks again for the info,
Robert