how wicked is your cam?

[DarkoStoj]

just for fun, check your cam specs, and see how they stack-up in tech author David Vizard's "Advertised Overlap Chart" below:

10* - 40* towing
30* - 60* ordinary street
50* - 75* street performance
70* - 90* street/strip
85* - 100* race
95* - 115* Pro race

Here's how you calculate your advertised overlap:

Add your intake and exhaust advertised duration (duration at .050 will not give you the correct overlap)
Divide that answer by 4
Subtract the lobe seperation angle (LSA) from that answer
Multiply that answer by 2, and you have it!

Now compare your adv overlap to the chart above, to see how wicked your cam really is. Most people think their cam is hotter than it really is, so don't feel bad if you are in that group, since you will not be alone. This can give you an idea of what to shoot for on your next rebuild

 

[Lay It]

60. Ford B-303 Cam

 

[iskwezm]

mine came out to 100

 

[12sec67]

mine came out to 100

mine came out to 62 with the ford racing X-303 cam

 

[Fast63]

mine is 62, comp 282S solid flat tappet. An E-303 would be the same.

But what's up with that chart dude. What category are you in with 35? towing or ordinary street? What's with the "overlap" HAHAHA

 

[brianj5600]

56 here. 280 on 112lsa Crane.

 

[gonzothegreat]

mine is 60
the cam is a compcam 35-430-8
http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=35-430-8

 

[SNAKEPILOT]

The same cam in a bigger engine will be less wicked. The formula doesn't take into account cubic inches.

 

[66forfun]

69 with flat tappet cam. Wanted the old school "cammed" idol that the roller cams just don't provide. The xpipe seemed to have smoothed out the idol though.

 

[iskwezm]

Wanted the old school "cammed" idol that the roller cams just don't provide.

Mine is a roller and slightly lumpy

 

[66forfun]

^oops, i know they are out there but most sound tame.

 

[D.Hearne]

69 with flat tappet cam. Wanted the old school "cammed" idol that the roller cams just don't provide. The xpipe seemed to have smoothed out the idol though.

I've used both the B303 and Z303, and both have a healthy lope at idle (not idol) Both with open headers make enough noise and vibes to shake stuff off the shelves in my shop. THAT REALLY impressed my teenaged son and his friends.

 

[blown65]

Mines 84. 292/300 656/656 lift 266/274 .050 Solid roller.

You cant tell me though a 300 adv duration cam in a hyd flat tappet is the same as a solid roller with way more aggressive ramps.

 

[lauras70mach1]

69 with flat tappet cam. Wanted the old school "cammed" idol that the roller cams just don't provide. The xpipe seemed to have smoothed out the idol though.

My wife's car has a roller cam and it sounds OK:

http://www.youtube.com/watch?v=4iUbIJ0Bmts

 

[woodsnake]

*33* ?
performer rpm, .496/520 lift, 290 I 300 E. 590/4 =145, -112lsa 33.
Right?
That sucks!

OK, using a calculator, I got 35.5. still sucks...
Multiply that answer by 2,= 71.
better!

 

[D.Hearne]

*33* ?
performer rpm, .496/520 lift, 290 I 300 E. 590/4 =145, -112lsa 33.
Right?
That sucks!

OK, using a calculator, I got 35.5. still sucks...
Multiply that answer by 2,= 71.
better!

You've basically chosen an "RV" type cam here. Good for bottom and mid range. Mileage should be OK too. The advertised duration numbers are misleading. Look at the @.050 numbers, they'll be something like 214/224 or 218/228

 

[iskwezm]

*33* ?
performer rpm, .496/520 lift, 290 I 300 E. 590/4 =145, -112lsa 33.
Right?
That sucks!

OK, using a calculator, I got 35.5. still sucks...
Multiply that answer by 2,= 71.
better!

I had that cam in my 289.I liked it,streetable,good sound and made good power.Not a RV cam IMO.

 

[woodsnake]

EDL-7122
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,500-6,500
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 234
Duration at 050 inch Lift: 224 int./234 exh.
Advertised Intake Duration: 290
Advertised Exhaust Duration: 300
Advertised Duration: 290 int./300 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.496 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.520 in.
Valve Lift with Factory Rocker Arm Ratio: 0.496 int./0.520 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash: 0.000 in.


Oh, the 224/234 at 050. I got ya.
I was real disapointed when I looked at the reults from the magnum cam I have in a box for my next 289.....

 

[D.Hearne]

EDL-7122
Cam Style: Hydraulic flat tappet
Basic Operating RPM Range: 1,500-6,500
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 234
Duration at 050 inch Lift: 224 int./234 exh.
Advertised Intake Duration: 290
Advertised Exhaust Duration: 300
Advertised Duration: 290 int./300 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.496 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.520 in.
Valve Lift with Factory Rocker Arm Ratio: 0.496 int./0.520 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash: 0.000 in.


Oh, the 224/234 at 050. I got ya.
I was real disapointed when I looked at the reults from the magnum cam I have in a box for my next 289.....

Ok, a step above an "improved" RV type cam. The @.050 numbers are more than I figured it to be.

 

[65ShelbyClone]

An easier way to calculate the overlap is to simply add the intake opening degrees and the exhaust closing.

My Crane Powermax 2031 came out to 55° of overlap using both methods.

Lift:
intake - 0.513
exhaust - 0.529, both with 1.7 rockers.

Advertised Duration:
intake - 276°
exhaust - 282°

intake opens at 28.0° BTDC, closes at 68.0° ATDC.
exhaust opens at 75.0° BBDC, closes at 27.0° ATDC.

112° LSA.