Analysis and opinions of cam specs sought

yours must be a much older version of the current http://www.lunatipower.com/Pro...aspx?id=3020&gid=258

as the 'previous' number 6116 is still not the number on your sheet

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FWIW the cam is doing pretty much what they said it would do, 1500-5000 rpm

it sounds to me like you need to see a man about a cam

+1. It's the cam. This is what we could call an RV cam. Made for high torque off of idle. 5000 is most likely it's limit.

It is milder than the stock CJ cam.

Tem

I got your private message. Based on "advertised duration" the exhaust valve lobe of that cam is opening your engine's exhaust valve at 70 degrees BBDC. That's 10 degrees too late which is very significant. The torque curve will drop like a brick at "higher rpm" because the engine is working too hard to push the exhaust gases out. I've run into this problem many times over the decades. The cam is indeed at least one of the issues, I can't say if there's others at this point. I know you've read some of my posts at various internet places. So you know I have a jaded opinion about the cam offerings from the commercial cam grinders. Cams like the one in your engine are good examples of what led me to becoming fed-up with the offerings from the cam grinders back in the 1980s. They are "poser cams".

Hot rod 351C cams ... I don't care about them! They give the engine a lopey idle, because the cam grinders think that's what sells cams. And obviously it does. I can suggest legitimate 351C street cams with my eyes closed; it ain't rocket science. I come from an age when real world performance meant more than a lopey idle or a dyno sheet. I'll help you any way I can my friend, any questions, whatever, just ask away. I'm here ... and we're all here. I don't want to be the center of attention, many forum members can help; Pantera Doug, etc. There are guys operating legitimate high performance businesses too. There are also plenty of members running cams having specs suggested by me to give you back-up, if they aren't afraid to respond. Unfortunately that's the rub ... to agree with me means to be ostracized in other places. There are egos and commercial interests involved.

Wow, thanks for the help. I don't have to worry about why I was hitting the "rev limiter" at 5k. The cam was installed in the 70's during the gas shortage, well there is not a shortage now. It's coming out. I think with a new cam, springs and rollers and add in the Holley 780 and a Strip Dominator I'll have all that I need.
Thanks for the info.

Wow. No one ever RECOMMENDED me? I've had guys come looking for me with a shot gun but that's another story.

Compcams has a listing on the 289hp Ford for a hp stock cam plus 1.

I didn't look for it under the cleveland heading but I think essentially that is what you want in your car.

The stock CJ cam is good to about 6,000. Maybe 6,200. Then it just shuts off BUT it has a nice idle and a nice burbbly sound to the exhaust.

Yours is what the manufacturer called a 268. There is no such term to qualify the CJ cam so that you could compare but you are likely into a 280 to 282 advertised duration.

A hydraulic lifter cam with 350 pound springs will let you rev it to the 7,000 rpm area if you so choose but in a street cleveland that isn't neessary at all.

Look at the video in the other thread of the blue car on the track. That car has Webers and 180 headers with open exhausts.

I don't think I saw it go over 6,700 rpm's.
It just isn't necessary unless you were trying to beat one of the factory teams and fat chance at that. They have mega bucks.

Why don't you check in with the CompCams tech help line and tell them what you want and see what they recommend. Bet cha' a nickle it's what I just said.

I have noticed that they tend to recommend about a one notch calmer cam than I would.

Don't be afraid of something like a .580 lift. It won't hurt anything and will give you the top end that you are now missing.

Incidentally, the Webers get 22 mpg and the Holley about 14. You can make them run on regular gas too.

The ONLY place your cam would save you gas is at the 550rpm idle it's got. That's all.


What George has said in the past about these aftermarket cams being used in everyday traffic being uncomfortable is absolutely true but are you going to drive this car everday in traffic like we did in the 70s? I doubt that.



This one is about what the stock CJ cam was.

http://www.compcams.com/Compan...s.aspx?csid=842&sb=2

I was thinking this one would be about a +1:

http://www.compcams.com/Compan...s.aspx?csid=843&sb=2

I am using this one even with the Webers but you would need to be somewhat of a dysfunctional sociopath to use it:

http://www.compcams.com/Compan...s.aspx?csid=861&sb=2

Here's a hydraulic flat tappet cam spec, based on the M code camshft:

Ford 351 Cleveland hydraulic flat tappet street cam
Grinder: Bullet Cams
Lobes:
Intake #HF275/328 (Asymmetric lobe)
Exhaust: #H287/3283 (Asymmetric lobe)
112° ATDC intake lobe mathematic centerline
117° BTDC exhaust lobe mathematic centerline

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275°/287° advertised duration (281° average)
223°/235° duration at 0.050"

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52°/52° hyd. intensity
Overlap at 0.050” = 0°
Lobe separation angle = 114.5°

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0.328"/0.3283" lobe lift
0.567”/0.568” theoretical valve lift (1.73:1 ratio)
0.549”/0.550” factual valve lift [(lobe lift – 0.0050) x 1.70]

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EVO = 80.5° BBDC
IVO = 25.5° BTDC
Overlap = 52°
EVC = 26.5° ATDC
IVC = 69.5° ABDC

With 0.550" "true valve lift" (0.567"/0.568" theoretical) yet only 52° overlap this is absolutely an amazing spec for a street cam. Very hot lobes, in fact the intake lobe is Ford specific; it is too hot for a smaller diameter GM tappet. But the lobes are not too hot for a street engine in this day and age. I expect the cam to wear just fine as long as it is properly polished and nitrided (hardened), then broken-in properly, with the proper spring force being used (about 120 on the seat and 315 over the nose), and with the best oil (Valvoline VR1) being used.