low lift flow on all out drag engines

[289nate]

Charlie, I would think the person designing the cam would want to be in control of the aspects of the engine regarding intake and exhaust sides for the specified displacement, budget, and rpm range in an all out effort. Otherwise, they are designing a cam around what you have and not based on what they can do.

289nate,

The big numbers I get for my street engines are because the cam is speced to suit the engine not the cam grinder!
DV

You don't really see any cylinder head specialists get very specific on cam design and vavletrain specifics. But I can't think of any good cam designer that cannot line up a set of flow curves (obviously with all the specifics about the cylinder head and combo) and tell you what they would prefer to work with. You yourself would want to have a say in the valve job for the application before it was done even if you were contacted to just do a cam. That's my point.

Completely different when one very competent person is in charge of the entire build. Sadly too many times that is far from the case.

[289nate]

I have read all of this thread and the one remark that sticks in my mine is, (cylinder heads have changed as valve train parts have got better). I believe it is the other way around ??? Mark H.

Chevy and Ford started using hydraulic roller cams with their old school cylinder head castings. Since then, cyinder heads have changed drastically. A stock LS3 head from a SUV is what used to be considered a race only casting.

[David Vizard]

289nate,

In your post you said:- You don't really see any cylinder head specialists get very specific on cam design and vavletrain specifics. But I can't think of any good cam designer that cannot line up a set of flow curves (obviously with all the specifics about the cylinder head and combo) and tell you what they would prefer to work with. You yourself would want to have a say in the valve job for the application before it was done even if you were contacted to just do a cam. That's my point.

Completely different when one very competent person is in charge of the entire build. Sadly too many times that is far from the case.

I think there is a little confusion on my part as to what you are exactly saying here. My response at this point is:-You yourself would want to have a say in the valve job for the application before it was done even if you were contacted to just do a cam. That's my point.

Yes thats correct.

When I spec a cam out there are dozens of things I need to know to hit the optimal spec on the mark. If I cannot get the data I require then I am back to doing a guessing job. Fortunately I have a huge amount of experience so my guesses are pretty good by all accounts.


Completely different when one very competent person is in charge of the entire build. Sadly too many times that is far from the case.

I absolutely could not agree more!


DV

[swampbuggy]

289nate...i understand what you are saying and i agree cylinder heads have advanced a TON in the past 20 years. What i meant by what i stated was (is) we do NOT apply (use) the same camshaft cores/profiles, rocker ratios etc. that we did on older poorer cylinder heads. Mark H.

[Old School]

DV did change the valve job. I had a typical 45 degree seat. He changed the degrees and added radius. Which dropped high lift flow and gained llf. On the super short cam that may have helped. I developed those ports without llf consideration since they are so small. Thanks, Charlie

Guess my question will remain un-answered ?

Randy

Randy,
I can address this on the 2 heads are better than one thread.
DV

Why address it on another thread. I would like to hear this discussion. No reason to not discuss it here and now.

[289nate]

289nate,

In your post you said:- You don't really see any cylinder head specialists get very specific on cam design and vavletrain specifics. But I can't think of any good cam designer that cannot line up a set of flow curves (obviously with all the specifics about the cylinder head and combo) and tell you what they would prefer to work with. You yourself would want to have a say in the valve job for the application before it was done even if you were contacted to just do a cam. That's my point.

Completely different when one very competent person is in charge of the entire build. Sadly too many times that is far from the case.

I think there is a little confusion on my part as to what you are exactly saying here. My response at this point is:-You yourself would want to have a say in the valve job for the application before it was done even if you were contacted to just do a cam. That's my point.

Yes thats correct.

When I spec a cam out there are dozens of things I need to know to hit the optimal spec on the mark. If I cannot get the data I require then I am back to doing a guessing job. Fortunately I have a huge amount of experience so my guesses are pretty good by all accounts.


Completely different when one very competent person is in charge of the entire build. Sadly too many times that is far from the case.

I absolutely could not agree more!


DV

Sounds like I wasn't clear enough. Hard to convey intention in typed words some times. We agree!

[289nate]

289nate...i understand what you are saying and i agree cylinder heads have advanced a TON in the past 20 years. What i meant by what i stated was (is) we do NOT apply (use) the same camshaft cores/profiles, rocker ratios etc. that we did on older poorer cylinder heads. Mark H.

Very true. I was only suggesting the use of better vavletrains from the factory opened the door for incredible heads on things such as those on the stock 6.2L in my big old GM SUV.

[David Vizard]

Guess my question will remain un-answered ?

Randy

Randy,
I can address this on the 2 heads are better than one thread.
DV

Why address it on another thread. I would like to hear this discussion. No reason to not discuss it here and now.

Because I had intended from the start to address this cam situation in that thread so that is where it is going and it will be in my good time not anyone else's..
DV