Camshaft Article

paul_huryk  Mar 31 2006 - 4:42pm   

In another section, I explained how cams work, powerbands based on duration and how important valve lift is. There are two other areas of camshaft specs you need to know before you buy:Lobe Separation and hoe to figure out the duration you need in engines larger or smaller than 350ci. Lobe separation is the amount of degrees between the intake and exhaust lobes of a camshaft. Knowing about the separation is important because it directly affects midrange (and low end to a degree) torque, it also affects how much vacuum a motor will pull at idle (more vacuum means a better idling-less racy motor). Most stock cams from chevy motors have a separation of between 114 and 118 degrees, these cams are not optimized for power, but for economy. If you make the centerline 112 degrees, the motor will idle and make more midrange torque than a stock cam with the same durations and lift. If you want even more midrange, you can use a cam with 108 degrees separation, but it will idle poorly, and the computer will think something is wrong because the vacuum is low. Most street cars work extremely well with a cam of 112 degrees separation. One word about separation and supercharging / superchargers like cams with 115 or more degrees of separation. Why? Because you use the supercharger to force more air in than it can without, having a small separation makes the boost go in the intake valve and straight out the exhaust (because it is open longer into the intake stroke). The way to calculate the duration needed on a smaller or larger motor is easy; for every 25 cubic inches above a 350, add 5 degrees of duration to make power at the same peak as a 350. If the motor is smaller than a 350, subtract 5 degrees of duration for every 25 cubic inches the motor is smaller than a 350.

This is a list of every replacement roller cam for small block chevys (factory roller).

Competition Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
08-300-8 206/210 .450/.480 .480/.512 112deg None
08-302-8 210/220 .480/.480 .512/.512 112deg None
08-304-8 210/220 .500/.510 .533/.544 112deg None
08-306-8 230/244 .510/.540 .544/.576 112deg None

Crane Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
104101 184/194 .384/.407 .410/.434 106deg None
104104 184/204 .384/.429 .410/.458 108deg None
104111 194/204 .407/.429 .434/.458 111deg None
104121 204/214 .429/.452 .458/.482 116deg None
104125 208/214 .438/.452 .467/.482 112deg None
104124 214/220 .452/.456 .482/.486 112deg None
JVR4 210/224 .516/.516 .551/.551 112deg None
10HR00022 206/214 .497/.497 .530/.530 112deg None

Lunati Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
50160 213/218 .446/.468 .476/.499 110deg None
50155 215/218 .489/.503 .521/.536 113deg None
50156 232/242 .510/.525 .544/.560 108deg None
50162 242/252 .525/.540 .560/.576 108deg None

SLP Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
51002 206/214 .470/.490 .501/.522 112deg None
51006 214/224 .470/.490 .501/.522 115deg 1992 Firehawk OE
51010 224/232 .490/.510 .522/.544 112deg None

Accel/Lingenfelter Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
74211 211/219 .503/.525 .536/.560 112deg None
74216 216/218 .462/.470 .493/.501 112deg None
74219 219/219 .525/.525 .560/.560 112deg None

TPIS Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
700-136 212/226 .483/.520 .515/.554 112deg ZZ9 Cam
700-137 210/218 .492/.492 .525/.525 112deg None
700-150 218/219 .415/.433 .443/.462 108deg Super Profile L98

GM High-Performance Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
10134334 235/235 .480/.480 .512/.512 114deg ZZ1 motor cam
10185071 208/221 .474/.510 .510/.544 112deg ZZ3 motor cam
24502586 218/228 .492/.492 .525/.525 112deg LT4 motor cam

GM Stock Cams
Model Number .05" Duration 1.5:1 Lift 1.6:1 Lift Lobe Sep. Notes
14093643 202/207 .404/.415 .431/.443 114.5 87 350,305man
10088155 179/194 .350/.384 .373/.410 109deg 87 305 auto
10066049 207/213 .415/.430 .443/.459 117deg 88-89 350,305
10111773 202/207 .413/.428 .441/.457 114.5 90-92 350,305

 
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