I guess the real question is… will YOU notice the difference?
If I was building the engine to do a particular task on a race track, I would want what I ordered.  On the street, you will never know the difference.

Totally up to the one that shelled out the money.  If he is handing you an off the shelf grind you could have bought from Summit for less money, I would send it back. If he sent you that because he custom ground it and his cam core would only allow that much lift because of size limitations, and he cannot source one that will make that size, that might be a different thing. Did he say why it was that way?

I agree with Sal and MS.
I'll offer the following. 
How do know your measurements are more accurate than the cam grinder? 
I'm not questioning your, or his, abilities, but I've worked with difference machinists and their measurements are not always exactly the same even when using the same measuring instruments.  Also, when was the last time the calibration of measuring instruments completed?  
 

BobE wrote:

I agree with Sal and MS.
I'll offer the following. 
How do know your measurements are more accurate than the cam grinder? 
I'm not questioning your, or his, abilities, but I've worked with difference machinists and their measurements are not always exactly the same even when using the same measuring instruments.  Also, when was the last time the calibration of measuring instruments completed?  
 

My thoughts exactly.  Its like checking your installed centerline.  If you're within 2 degrees I wouldn't try and adjust it.  There's enough hysteresis in your measuring equipment that you could be off by that much.  Plus a change of 2 degrees might move the powerband 100 RPM.

Stick some 1.7:1 ratio rockers on the exhaust and call it a day?

That would give 0.548 lift.

In existing configuration, the lift on the cam is off by 0.00875” at the lobe

Last edited by MS (1/13/2024 5:32 PM)

2.64 % error Sal.

1.7 rockers would make it 3.39% more.

Last edited by Nos681 (1/13/2024 9:17 PM)

jkordzi wrote:

Thanks but my concern is just with whether any of you folks would reject this cam, based on the requested exhaust lift being 0.516" when I requested 0.530."  The 0.516 figure is from the cam card and I verified it when I degreed the cam.

TKOPerformance wrote:

BobE wrote:

I agree with Sal and MS.
I'll offer the following. 
How do know your measurements are more accurate than the cam grinder? 
I'm not questioning your, or his, abilities, but I've worked with difference machinists and their measurements are not always exactly the same even when using the same measuring instruments.  Also, when was the last time the calibration of measuring instruments completed?  
 

My thoughts exactly.  Its like checking your installed centerline.  If you're within 2 degrees I wouldn't try and adjust it.  There's enough hysteresis in your measuring equipment that you could be off by that much.  Plus a change of 2 degrees might move the powerband 100 RPM.

 

Did you discuss it with the cam company?  Did you pay for a custom grind?  In my experience, cam companies have probably 50-75 part numbers for small block Ford cams they publish.  These are easily found on Summit's website, etc.  However, what you don't see is that they actually have thousands of part numbers for the small block Ford.  They don't publish all of them for a lot of reasons.  However, when a customer requests a custom cam the first thing they do is go through those unlisted part numbers and see if they can find a match or something that's close enough.  So I'm wondering is that's what they did for you.  If you didn't pay to have the cam custom ground to your exact specs then you probably just got what you paid for.  I doubt they thought there was an appreciable difference between the cam they sent and the specs you provided, especially when there a potential variables you aren't considering like ramp design.

Personally, I've never called a cam company and tried to spec my own cam.  I give them as much information as I can about the car, the engine, my power goals, and the use of the car and had their tech guy pick the cam for me.  If part of your discussion was like that, again, they may have simply sent you the cam they felt was best.  In that case I trust the company with hundreds of thousands of hours of dyno time more than I trust myself.  

So, long story short, would I reject it?  Probably no.  I'd just want to make sure I got what I paid for.  So long as I did, and the cam company is confident he cam they sent will meet my goals I'd stab it into the engine and move on.