Camcraft-Cams



Some thoughts on choosing a proper cam: STREET CARS

Be absolutely sure of your gear ratio when selecting a cam.

1- The first thing to do in selecting a cam is to determine top speed in high gear (not overdrive). If 6,000 rpm = 150 mph in high gear and you will never see that speed then you definitely don’t need a cam with 6,000 rpm power. Tuning for power at too high an rpm is a very common mistake.

2- A car with 3.08 gears will go 150+ mph @ 6,000 rpm. 5,000 rpm still = 125+ mph while 2,600 = 70 mph. It makes a lot more sense to tune the engine for power in the 2,000 to 4,500 rpm range. You can get good fuel economy as well as better performance. Any cam bigger than stock will make more power at high rpm. It just doesn’t make sense to select a cam with max power at 5,000 rpm if it will spend most of its life below 3,000 rpm. Below are common rpm=speed ratios. All are based on a 26-inch diameter tire.

2.73 @3000 = 85 mph,  3.55 @3000 = 66 mph,  4.10 @3000= 57 mph
3.08 @3000 = 76 mph,  3.73 @3000= 62 mph
3.23 @3000 = 72 mph,  3.90 @3000= 60 mph

3- If you have big heads you definitely need a smaller cam than if you used the stock heads. Failure to realize this will result is a big loss in low end and midrange throttle response. It will likely make great power at rpm levels you don’t even want to see.

4- Be careful of using big carbs. A 650 cfm carb is plenty for all but the most radical 350 engines, even for strictly racing. A 750 may make more top end power but it gives up a lot in low-end throttle response and midrange torque. This is especially true when you have big heads. The fact that your buddy ran faster with your 750 than his 650 only means there was something wrong with his 650.

 

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54 Atrium Trail
Arden, NC, 28704

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Phone (828) 681-5183
Toll Free (800) 426-2261
Fax (828) 681-5185

Email: charles@camcraftcams.com

 

Happy Customers

Charles,
Thanks for the great cam and kit.  With your 240/240 .410 lift lobes on a 110 center we made 365 rwhp in our 331" Nova with a 2-bbl carb, about 40 hp up from the Comp cam we ran last year.  The torque peak was at 4500 rpm and the power peak was at 6500 rpm, well suited for the long uphill road sections we use.  I had no problems at all with the engine, no valve lashing was necessary and we used one set of plugs for the entire race. We finished 2nd in our class behind a Corvette, and eighth overall in a field of 70+ cars.  We were complimented frequently on how fast the little Nova ran, finishing well ahead of several 366" 4-bbl cars.  If only we could corner with the Vettes....

Thanks again,
Mike
Fairfield, CA

...read more Testimonials HERE


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