I see a lot of cam threads with general suggestions such as Duntov cam or L79 cam, usually without real info on specs. I spent a little time compiling a few factory cam specs for reference to see how they stack up. Info is all pulled from internet resources, so please call it out if there are any errors.
GM Part # 3736097 283 -270 hp "Duntov Cam" SOLID Lift .395/.401 Dur @ .050 228/230 LSA 110 Comp Cams grind 287S (.395/.400 lift, 228/232 dur, LSA 110) 098 cam is same as 097 cam. 098 is the casting # 097 is the p/n # 3849346 327 - 365 hp "30-30 Cam" SOLID same pn cam for 1969 Z28 302 Lift .455/.455 or .485/.485 both listed Dur @ .050 254/254 LSA 115 Comp Cams grind 346S (.485 lift, 254 dur, LSA 114) 3972178, 3972182, 12364054 1970 Z28 350 - 360 hp Lift .459/.485 Dur @ .050 242/254 LSA 116 3863151 L79 327 - 350 hp HYDRAULIC Lift .440/.440 or .447/.447 both listed Dur @ .050 220/220 or 222/222 LSA 114 Comp cams grind 151H (.447 lift, 222 dur, LSA 114) 3896962 L82 late 70's vette HYDRAULIC Lift .450/.460 Dur @ .050 222/222 or 224/224 LSA 114 3896929, 3733431, 14060651 327 300hp HYDRAULIC Lift .390 / .410 Dur @ .050 195/202 LSA 112
Looked up a few modern grinds, the ever mysterious RV cam for comparison. These are very common replacement upgrade cams. Most lifts are in the .440 to .470 range, dur @.050 from 214-230. Above mid 230's starts to get into the range where vacuum suffers, a mild stall is needed, a sharp tuner can extend that range a bit RV CAM 1 (summit) Lift .450/.450 Dur @ .050 218/218 LSA 106 RV CAM 2 (summit) Lift .443/.465 Dur @ .050" 214/224 LSA 112 RV CAM 3 / street performance (summit) Lift .465/.465 Dur @ .050" 224/224 LSA 112 RV CAM 4 / street perf (isky 190162) Lift .465/.465 Dur @ .050" 208/208 LSA 108 #4 is interesting, was from Isky, pretty good lift for such a short duration. Whats the thought on this one for a smaller displacement engine?
Nice job Indy, that should help a lot of guys always asking but not doing the research you did. I have always felt that most aftermarket mild cams are better than the GM cams that most people like to talk up. Buddy Morrison of Rehr sp. and Morrison in an article in National dragster 20 yrs ago felt the same way. Pat
Thank you for posting this. I too had compiled a bunch of cam specs found from searching the net. I had them written down on a yellow post-it note which was stuck to my desk for a long time, and I'd look at it frequently, especially when any cam threads came up. But eventually the adhesive wore out and the note floated off somewhere and I have no idea where it is now. So it's nice to have a place to come back to for reference, won't have to go searching all over the net again to find those specs of those classic cams. Thank you again!
One drawback of many stock cams is the nearly same intake and exhaust duration. Stock heads are notoriously poor on exhaust side flow, and a big reason for why newer aftermarket cam profiles typically have 10 or so more exhaust duration. Newer profiles also tend to have more aggressive ramp rates and lift numbers, to get a little more area under the curve for a given duration. Just my experience, the 327/300 cam is way too mild for any performance. Even the 327/350 is pretty mild and works with stock converters and taller gears. Especially when these or other cams are used in 350 or larger displacement bigger engines mellow out a cam. Thanks for compiling the data. Sent from my SM-A102U using The H.A.M.B. mobile app
Here is a more complete list of SBC cams: Chevrolet Factory Cam Specs by part number Part # Lifter type--duration at .050 In/ex--Lift in/ex--centerline--description Small Blocks 3849346 Mechanical - 254/254 - .484/.484 - 114 - 327 365HP& Z-28 302 3863151 Hyd. - 221/221-.447/.447-114 - 327-350HP, L79 3896929 Hyd. - 195/202 - .390/.410 - 112 - 327 300 HP 3896962 Hyd. - 222/222 - .450/.460 - 114 - 350 L-46, L-82 3927140 Mechanical - 257/269 - .493/.512 - 112 - Off Road 3965754 Mechanical - 262/273 - .488/.509 - 112 - 2nd design road race, short track 3972178 ? 3972182 Mechanical - 242/254 - .459/.485 - 116 - 70 LT1 360 & 370HP, 71 LT 330 HP 10134334 Hyd. Roller - 235/235 - .480/.480 - 114 - 350ZZZ and ZZ2 Crate Motor 10185071 Hyd. Roller - 208/221 - .474/.474 - 112 - 350 345, ZZ3&4 Crate Motor 10224241 Hyd. Roller - - 92-94 GenII, LT1, 350 10243779 Hyd. Roller - - 94-96 Gen II, L99 265 V-8 12353914 Hyd. - 180/194 - .378/.401 - - GM Crane Lo speed Hi torque 12353915 Hyd. - 194/204 - .401/.423 - 104 - GM Crane street 12353916 Hyd. - 204/214 - .423/.446 - 110 - GM Crane 305-350 street legal 50 states 12353917 Hyd. - 204/214 - .420/.441 - 112 - GM Crane nan-emissions vehicles & off road 12353918 Hyd. - 214/224 - .442/.465 - 112 - GM Crane marine & off road 12353923 Hyd. - 224/234 - .465/.448 - 114 - GM Crane off road 12364050 ? 12364051 ? 12364052 ? 12364053 ? 12364054 ? 12370845 Hyd. Roller - 214/224 - .488/.509 - 112 - Off Road, lobe for mech fuel pump 12370846 Hyd. Roller - 222/230 - .509/.528 - 112 - Off Road, lobe for mech fuel pump 12370847 Hyd. Roller - 232/242 - .539/.558 - 112 - Off Road, lobe for mech fuel pump 12551142 Hyd. Roller - 203/210 - .476/.480 - 115.5 - 96 350 LT4 w1.6 roller rockers 12551705 Hyd. Roller - 201/208 - .447/.459 - 112 - 95-96 Gen II, LT1, w center dowel pin 14088843 Hyd. - 202/206 - .403/.415 - 115 - 305 HO, 83-86 14093643 Hyd. Roller - 202/206 - .403/.415 - 115 - 87 350 Corvette, IROC Camaro 24502476 Hyd. - 121/220 - .435/.460 - 112.5 - 350 300 crate motor 24502586 Hyd. Roller - 218/228 - .525/.525 - - 96 LT4 H.O.T. crate motor, use with 1.6 roller rockers NA Hyd. Roller - 202/210 - .472/.478 - 111 - 97 Gen III LS1 Corvette 350 uses 1.7 roller rockers Here is the 140 cam info in more detail, this is from crane who sells a copy of it: Part Number: 968821 Grind Number: 3927140 Engine Identification: Start Yr. End Yr. Make Cyl Description Engine Size Configuration Valve Setting: Intake .024 Exhaust .026 HOT Lift: Intake @cam 3286 @Valve 493 All Lifts are based on zero lash and theoretical rocker arm ratios. Exhaust @ Cam 3412 @Valve 512 Rocker Arm Ratio 1.5 Spring Requirements: Triple Dual Outer Inner Part Number 99893 Loads Closed 120 LBS @ 1.875 or 1 7/8 Open 296 LBS @ 1.415 Recommended RPM range with matching components Minimum RPM 4200 Maximum RPM 7000 Valve Float 7500 Cam Timing: TAPPET @.050 Lift: Opens Closes Max Lift Duration Intake 20.5 BTDC 56.5 ABDC 108 257 ° Exhaust 70.5 BBDC 18.5 ATDC 116 269 ° CENTERLINE INT 108 EXH 116 LOBE SEP 112 __________________
I've found the aftermarket cams better overall. Personally I like to go mild on the cam and run the best heads I can to get power.
Bumping this up. If you look thru the cam catalogs for "RV" "Street Performance" small chevy cams. Most are based in the same lobes .443 .465 .480 then the lobes are moved around for whatever duration to set power band. Here's the factory L82 cam. We know this will idle well and pull vacuum or GM wouldn't have put it in a factory ride. 3896962 L82 late 70's vette HYDRAULIC Lift .450/.460 Dur @ .050 222/222 or 224/224 LSA 114 It's very similar to most street performance cams. Many of those cams were released in the 70's and 80's with 76cc or double humps being the standard heads. The aftermarket used more split profile cams to give the exhaust side more lift or duration to bolster the performance. You'll see many street performance cams in the following range 443 / 443 218 / 218 443 / 465 218 / 224 465 / 465 224 / 224 Same couple of lobes or durations just mixed for the different applications and power bands that make up most of the "upgrade" chevy street performance cams. Comp and other have newer versions of these with different lobe shape and lift, but hydraulic lifters can only handle so much ramp on the lobe. Above .465 The lobes generally go to .480 .490 .500 with durations in 220 to 232 range. Pushes the power band up to 6000-6500 rpm based on duration. This takes it more into street strip, less vacuum, rumpity idle, stall speeds, more gear. You'll find the same pattern - a few lobes being mixed with durations to give different cam profiles. In general, the duration sets your powerband, I'm not getting into LSA. For a driver, l look at where I want the powerband or peak torque based on vehicle weight and gear - then try to find the cam that has the most lift with the duration range I want.
Is my memory failing or was there a GM cam back in the late 60's or early 70's referred to as the "White Paper" cam? This thread made that recollection pop into my head and I was wondering if anyone else remembers something like that. Great reference thread! Thanks. Lynn
Great info. Brings back memories of the 3927140 and 3965754 off road cams. Used them in a number of budget build engines and was never disappointed. Used the 140 cam in a 327 street engine with 492 angle plug heads. It pulled to 8200 rpm, mostly drivable. Used 754 cams frequently in 302 track engines. The price was right and midrange power was its strong suit.
For some reason I was pretty excited when I took my NOS L79 camshaft out of the factory GM tube, much more so than the General Kinetics, Crane and Comp cams in other engines.
@indyjps Both of these you listed above work really well in a rebuild. Assuming most people will opt for some type of headers, 4V carburetor and an aluminum intake manifold. 3863151 L79 327 - 350 hp HYDRAULIC Lift .440/.440 or .447/.447 both listed Dur @ .050 220/220 or 222/222 LSA 114 Comp cams grind 151H (.447 lift, 222 dur, LSA 114) 3896962 L82 late 70's vette HYDRAULIC Lift .450/.460 Dur @ .050 222/222 or 224/224 LSA 114 We used a variation of the L-79 151 camshaft on a tight 107 or 108 Duration for dirt racing in the 80s. It is still one of my go to camshafts for the SBC. I don't remember which company sold it but it was listed as the "Saturday Night Special." Summit Racing and Howard's have their own versions of it.
Sometimes I can't help but wonder what a guy's life would be like having lived in the land of sunshine and smooth roads rather than a place defined by 4 seasons, frost heaves, potholes and 6 months of them cold and snow covered. Would time go by faster or slower? If the quest was, which cam will get the best gas mileage per horsepower at 110kph cruising speed, think these two favorites from a by gone era would still make the list? I don't know, to me it's still a mystery because neither car's that had them, got good mileage, both were OT and 4spd cars. Bills OT 75Nova SS had the 151 grind. Kevins OT 70Nova SS had the 962 grind. I had the day job, wife, and 3 kids grind. And that in itself is a clue to why, I asked about time. Because if I put a cam in and lived in California, I'd figure out soon enough what effect it had on things. Up north, it could take a season or two. Not to be a nostalgia buzz kill, I do realize that money buys a who cares it's mine to do with attitude, but really, with a broad brush, in the bigger picture back then, both cars were winter drivers and -30 cold starts. Plugged in they'd start and sit idling to warm up. But gas was cheap, and you burnt your share of it. I keep coming back to not much past counting dollar bills filling the tank. Unless a guy is counting down the seconds in the quarter mile, both cars did that really well, it was cost to fill the tank that decided how much driving you would do. Guys now making a cam choice, might want to ask themselves, will that cam have an effect on my driving. Not only in terms of the further cost for upgrades to take advantage of what the cam offers, but also operating costs to do so once you have. Comp Cams Chevy Small Block Cams Tested - Cam Wars (motortrend.com)
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