Hold on there Pardner! NO one wants you to leave. We are truly only trying to help. The new cam you are looking at is better, but why not go for the best? Why go through all the trouble to change it, and not really make it an angry beast, which I am telling you Lou's car is. You don;t have to reinvent the wheel here. It's already been done. All you have to do is take the advice of the guy who has been down this road already, and pay more attention to his advice then software, or a counter guy. You are so close. Don't give up. Suck it up, and rethink everything that has gone down on this thread. Then do what best meets your goals after you have considered everything with a fresh set of emotions, and a fresh intellectual frame work to operate from within.

Sam

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True, but the phasing events are different. Any cam company that tells you different is full of it.
A Slant6 does take a different design of camshaft, and I would trust these slant guys on the subject before I trusted a computer. My .02....



Also true....but it musn't be accounting for the fact that you have too much to start with.
The correct cam will "move" cranking pressure around in a way that your engine can use it,(Which is something it's obviously not doing now) and you will take off faster.
Don't think of it as "losing" anything, just converting what's there into usable power.
Don't give up yet, just step out on what these guys are saying, and you'll have a ka-nasty mill in you car.
BBB

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225 Cubic Inches of Iron-Head American Muscle

225 bored .040 /.100 off block, Schneider Cam 224@.050~ .480 lift - Stock valves, blended bowls, Offenhauser intake with 500 Edelbrock carb

My engine is not like Lou's engine. I have to much compression.
I'am listening to all of you, but when I get the feeling that you are not listening to me, how can I follow blindly? I'll say it again. I have to much compression. Why can't advice be giving within certain perameters? Yes I should take out some compression, but is it impossable to make sugestions based on this high compression? Do you all really believe that in you quest to help me, have really taken into account for the high compression? Or do you think it's closer to "well its what I did"? (not having a CR problem)
Dan you never follow blindly. Why are you asking me to?

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Beg your pardon, Sam, but I do wish he'd just go away, and I don't mind saying it. My opinion may be shared by a few, by many, or by none on here, and that's fine with me. As far as I'm concerned, he's been nothing but a constant pain in the tuchus from the very start, all take and no give.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

...and immediately rejecting what you're told 'cause it doesn't match up with what your computer program said or what the nice man at Camz-R-Us told you. What was that you were saying about not following blindly...?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Let's continue to be supportive....

My advice has been: "take some compression out"...
If it were me, I would be pulling the head, not the cam.
(about the same amount of work if you think about it)

With some combustion chamber work, piston notching and a thicker head gasket, you can drop the C/R with-out tearing down the entire engine.
With your combo, it does not take a lot off CCs to get a significant drop in compression.
DD

From earlier calculations:
3.591 x 4.250 = 258+ CID and compression ratios for "final" chamber size are as follows:
8 to 1 @ 100+cc
9 to 1 @ 88 cc
10 to 1 @ 78 cc
11 to 1 at 70.5 cc
12 to 1 at 64 cc

There's a difference between following blindly and taking the time to correct your (mis)understanding of what's going on inside the engine. Yes, we know. You have too much compression. Nobody is overlooking that fact! I've gone back and read EVERYTHING (painful as its been) and EVERYONE is on the right track except the guys that are selling you parts. There's no "conflicting information," there are just different ways to approach the problem, but they all rely on the same underlying principle: use the cam timing events to lower the low-RPM cylinder pressure.

You can do that different ways- you can get a grind with more overlap. You can change the intake valve closing point and the exhaust valve closing points. You can retard the cam. The exact solution you pick depends on your budget and what you want.

What you need to get OUT of your head is that making these changes will kill your low-end power. RIGHT NOW, you're engine isn't getting anywhere near its theoretical low-RPM power because you've got your ignition timing set all wrong to try to suppress detonation, and its still detonating. When you make these changes, your engine's theoretical low-RPM torque WILL be lower, BUT you can now set your timing right and your ACTUAL low-end torque will stay the same or go up.

But I think I said this already.....

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Bren67Cuda904, I can understand your possition on all of this. Looking at your expeirance level ( I dont mean that in bad way, OK) and wide range of info that as been thrown at you, it is easy to see how confussing & frustrating it can be. I do see this with a lot of guys that have taken a road that they have never been down before, and they get to the piont that they are not sure whcih way to go, or what to do. No matter what you do though, you will come out with a better understanding of what you have gotten into. Even if what you do is wrong. SOmetimes doing the wrong thing can teach you better than someone showing you the right thing ( and there is always more than one right way).


I hope you do understand that most of us are just wanting to see you make this thing work ( well atleast some of us) As with my suggestion I gave, I gave because I believe it to be the best. Its what I would have done myself, and feel like it would have gave the results needed (but hey I could be wrong).

As far as a camshaft. I will have to agree that more duration will lower CCR. Also the Intake closing degree will effect CCR the most. The reason the slant six is differnt on its cam needs is because of the stroke,rod ratio ( it dont effect cam needs much but some), the bore & the head we have to work with.

It sounds like you have already put the order in for the grind you desided on, if so there is nothing left to do but try it and see where it goes. Hopefully it will take you where you need to be, if not then someone is not understanding the true nature of your build & I would seak out someone that does.


Good Luck, and even if some dont want to here it, please keep us posted on your results.


PS, if I gave a cam spec for your build from my own expeirance ( what I thought it should be with what I know) , I am sure many would say I was nuts. Hang in there, some of us are pulling for you.


Jess

You can notch a piston without removing it?

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67Cuda,FAST EZEFI,340cu,CR=10.25,RollerCam&Rocker (XR268HR,#20-810-9)(#1622-16)(EddyRPM#60779,#7576), (MSD6AL,#6425) A904, GearVendorsOD, 8 1/4,3.55:1, ClassicAir

Doc, your patience and goodwill run far deeper than mine, as it seems. I truly find that inspirational, but I'm still fed up with Brennan's shenanigans.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I will be the first to say that the preferred way to notch a piston is to have it out of the engine and on a milling machine.

I will go on to say that I have successfully notch a bunch of pistons while still installed in the short block and some while the short block was still in the car.

Many of these "shade tree" notch jobs were for valve reliefs on what I will call a "mule" or "claimer" engine... basically a serviceable factory assembly where you swap-in a race cam and a good head (or set of heads - V8 ) and end up with a performance engine on a budget.
It's not the kind of machine work I like to brag about but I did make a nice jig that installs into the threaded head bolt holes and accuratly positions the flycutter... it actually works pretty good.

Later in life, I am reading one of the national auto magazines and what do you know, here is the writer showing us how he put valve notches into pistons using a wood worker's router!
DD

Pardon me for not remembering all of this, but did you cc the head, and if you did, what is the CC of the chambers on yours?

Sam

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I based my final compression estimates on 705 cc "sweep volume".
There are still some questions about the final combustion chamber size. (Head chamber cc's + head gasket thickness + pistion dome/dish + area to the top piston ring = final combustion chamber size)
DD

Dan,

I feel pretty certain that you told some people if you don't like what is being written on a thread, then don't read it. This one is obviously causing you grief. I don't want him to go away and I want him to succeed. Since Doc and some others are willing to continue to help maybe you should just not read this thread anymore. I wouldn't want you to get an ulcer or anything.


Rick

c'mon bren... don't throw the towel on the last mile! you're there!

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Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.