How do you decide what cam you want

[marks73]

After reading through c9zx's post on head flow data it occured to me to ask the question:
How do YOU decide the specs of the cam your about to purchase?
I was always taught to chose the engine parts around the cam. Sort of a build it from the heart out theory. How do you decide what cam to buy when you do your build? Just curiouse!

[droptop73]

I would recommend giving the fine folks at Comp Cams a call. Describe to them what you have and what you want.

[c9zx]

A. What fuel octane limitations, if any are there? (This is a big deal)
B. What idle speed/quality and vacuum limitations are there?
C. What gear will be used?
D. If automatic, what is the convertor stall speed?
E. What type of exhaust system will be used?
F. What cylinder head will be used (flow numbers help here)?
G. What type intake will be used?
H. How will the vehicle be used?
I. At what RPM do you want peak power to occur and Max RPM?
J. What lifter type will be used?
K. What is the static compression ratio (SCR)?
L. Aim for an effective CR that matches the octane requirements.
The effective CR is set by the SCR, cam timing events (overlap and intake valve closing point, and rod ratio. Getting accurate and complete cam information is not as easy as it should be and usually requires speaking to the "right guy" at the cam company. VERY few 351C "right guys" out there. a cam that is right for a 351C 2V is not right for a 4V. A quasi-custom cam for your particular setup is usually not much more money than an off the shelf cam. I've had good luck with Crane, Schneider, Lunati, and others who are no longer around. See, nothing to it.

[Don65Stang]

^^^^^^^^^
What Chuck said.
Chuck is to engines like Scott is to body work.

[marks73]

Yeah but if all I'm after is that "pocketa,pocketa,pocketa"?

[73vertproject]

Chuck is right on the money, but the easy way is to follow Jeff's advice. I emailed Comp Cams, then talked to them on the phone, and it worked out great. If you want the sound of a fire breathing dragon and 4 miles per gallon, they can grind the right cam for you.

If you can figure out exactly what you want to do, that will help. Give them a call.

[Don65Stang]

Chuck is right on the money, but the easy way is to follow Jeff's advice. I emailed Comp Cams, then talked to them on the phone, and it worked out great. If you want the sound of a fire breathing dragon and 4 miles per gallon, they can grind the right cam for you.

If you can figure out exactly what you want to do, that will help. Give them a call.

That's funny...the fire breathing 4mpg grind. It's all about the overlap. Lol

[will e]

M. Are you going carb'd or fuel injected?
N. How much money can you spend? (roller vs non-roller)
O. How much time are you willing to spend maintaining the car (solid vs hydro)


I went with the comp cams. I was in a pinch to get the car running again and I had messed up a lifter/lob so I had to swap out the cam. This one had a little more duration. I offset that somewhat by going with rhodes lifters.

It's about the combination. One thing I missed was a higher speed converter.

[droptop73]

Yeah but if all I'm after is that "pocketa,pocketa,pocketa"?

Comp's Big Mutha Thumper it will give the choppy idle, maybe not much else...

[TommyK]

A. What fuel octane limitations, if any are there? (This is a big deal)
B. What idle speed/quality and vacuum limitations are there?
C. What gear will be used?
D. If automatic, what is the convertor stall speed?
E. What type of exhaust system will be used?
F. What cylinder head will be used (flow numbers help here)?
G. What type intake will be used?
H. How will the vehicle be used?
I. At what RPM do you want peak power to occur and Max RPM?
J. What lifter type will be used?
K. What is the static compression ratio (SCR)?
L. Aim for an effective CR that matches the octane requirements.
The effective CR is set by the SCR, cam timing events (overlap and intake valve closing point, and rod ratio. Getting accurate and complete cam information is not as easy as it should be and usually requires speaking to the "right guy" at the cam company. VERY few 351C "right guys" out there. a cam that is right for a 351C 2V is not right for a 4V. A quasi-custom cam for your particular setup is usually not much more money than an off the shelf cam. I've had good luck with Crane, Schneider, Lunati, and others who are no longer around. See, nothing to it.

Great guidance.

I have one comment. I think "H" should be "A". If you answer H first, many of the other blanks are much easier to fill in.