: L79 Cam
Aug 28th, 02, 10:57 AM
ok I got to thinkin Im supposed to build an L79 for this guys 66 nova. So I went up to GM and asked them for the specs on the L79 cam, they came back and said 320 duration at the lash point!!! How can that be, that thing wouldnt come around till like 4500. And then they gave me the duration at .05 which is 222. Ok so how can a cam have so much advertised duration and only have 222 at .05. Does gm rate that cams differently to the aftermarket ones and if so what is the real advertised duration. And if so how much compression could you run with this beast with vortec heads,good quench and sanded sharp edges. I tried Pat kellys calculater but it didnt turn out right, any experience on these motors on the street? Man I thought if it was a GM cam it wouldnt be very wild...... god bless the 60's uhh? I would like to run 92 but I can get 100 for $1.70 any ideas? its going in a 331does anyone know how it would act in a 355
Aug 28th, 02, 12:00 PM
There really are better cams around now than the old 350HP. Gm always put gentle ramps on their cams that is why at zero lash they look huge but in reality they aren't.
Aug 28th, 02, 01:05 PM
yes I know there are better cams, but this is stock replacement with the new heads and such. I guess he just likes the sound of 320 degrees of duration
Aug 28th, 02, 02:42 PM
I've got a box stock, original, L-79 with 41K miles in my '68 Vette and it runs fine on 92 octane pump gas. The motor has never been apart! I believe the advertised CR was 11.0. It's a little soft until around 3K rpms (M21, 3.70 rear), then all heck breaks loose. http://www.camaros.net/forum/biggrin.gif Very fun to drive.
'80 Camaro RS
383, AFRs, TH350, 3.73
'68 Corvette L-79
41K original miles
'02 Corvette convert.
'68 Corvette L-79 (http://www.chevelles.com/showroom/68vette.jpg)
'80 Camaro RS (http://www.chevelles.com/showroom/Bills80CAMARO.JPG)
'02 Corvette (http://www.chevelles.com/showroom/CorvetteFront.JPG)
Aug 28th, 02, 04:58 PM
The old -151, 350hp/327 cam is actually around a 290 cam by modern spec's and NOT GM's old off-the-wall spec's!
The old -346, or 30-30 solid, cam was per GM like a 346 cam but really about a 314 or so figured the modern way!
And, sure there are better modern cams out there but I gotta sneaking feeling that after all is said, the old-fashioned -151 cam will still be running after 120K miles where them modern fast action hi-po grinds will probably be worn out! Imho. pdq67
Aug 29th, 02, 02:06 AM
I ran a 327 with 10:1 and the "151" cam. It needs to be installed 4 degrees advanced to pump up the bottom end. Use variable duration lifters to furter fatten the bottom end and it will run great. That cam when set up this way is trouble free, does not need any fancy valve springs or screw in studs or guideplates and has an outstanding RPM range. It has slow ramps which allow it to rev higher than a newer style camshaft with a similar application. A proven combination.
Aug 29th, 02, 03:05 AM
Make sure your running a 4 speed or an automatic transmission with greater than a 2600 RPM stall speed torque converter and rear gears lower than 3.55:1 with this cam. Keep in mind the cam was desinged for a 4 speed car, it is a very peaky cam. HP and torque don't really begin to get good until your above 3000 rpm. Also run as much compression as you can get gas for, at least 10:1 (4 valve relief, flat top pistons are only 9.7:1 with 62CC heads).
I had it in a 350 with 9.7 compression and a 2400 RPM torque converter and 3.08 gears. It was a dog off the line.
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine (http://www.townisp.com/~markcanning/camaro/transparent%20air%20cleaner3.jpg)
Aug 29th, 02, 10:13 AM
thanks for all the responses. Im glad to hear that I can put some good squeeze with the cam. I saw an article with this cam and vortec heads in a 65 nova with the RPM manifold. It ran 12.2 with 373 out back and a m20. I have to disagree with the comment of the peaky power, I have built many of these and the cam with its 114 LSA has a wide range of power in even a 327 the only reason I could see it as peaky is that it aint a big block so it is gonna be soft till 3000. I like you may need to understand that if you dont have a 383 or 400, any other small block with be so to speak soft. I have never built one with vortec heads though, most owners like to use the edelbrouch RPM heads. I think the vortecs will be fine with a little bowl clean up. I too love the idea its a stock GM cam which promotes great durability and drivability along with power brakes in most cases. Do you guys have any ideas on the victor vortec? Is it worth the extra 60 bucks?
[This message has been edited by MoeSS396 (edited 08-29-2002).]
Aug 29th, 02, 02:52 PM
By modern measurement standards, the "151" cam has 221*/221* duration @ .050", .447"/.447" gross lift, 110* intake centerline, and 114* lobe separation (and uses all plain ordinary rockers and springs). I've had several Corvettes with this cam (4-speeds), and it's probably the best all-around zero-maintenance performance hydraulic cam Chevy ever made. It was never offered with an automatic - only with a 4-speed. Installing them 4 degrees advanced definitely improves low-end torque - I did my last one that way, and it made quite a difference.
'69 Z28 Fathom Green
Aug 29th, 02, 03:01 PM
Or drop the old -151 in a stock 350, L-48 engine at 10.25 to 1CR. or so and the stroke makes it very good! pdq67
Aug 30th, 02, 11:04 AM
any ideas on the victory manifold I have heard good things but I dont know if a 331 needs all that air? When do you guys think this cam will run out of steam with good hydo lifters. The one I seen run 12.2 shifted at 7000, I myself thought that was a bit high. does advancing the cam hurt top end pretty bad I mean this car has a 3500 stall. Thanks for all the info and stories
Aug 30th, 02, 03:48 PM
The cam has a great RPM range and will not run out of steam at the top end even if installed 4 degrees advanced. Advancing this cam does not hurt the top end but makes a bigger difference at the bottom end. If you have DD2K you can try to model the cam but it has unusual specs so the program does not do a very good job simulating it based on the available settings. You can definately see how the 4 degrees helps it run better though. I can not tell you about the Victor Jr on this combo. I used a Edelbrock Performer and it worked great on the street with a Q-jet.
Aug 30th, 02, 04:36 PM
Just my opinion, but I absolutely HATE that cam. The shop that built my first engine 9 years ago was instructed to build a 350 horsepower 350 Chevy for high performace street use. Evidently they believed that since this cam made 350 horses in the L79, it would also make 350 horses in my 350. Not so! The original L79 was an 11:1 compression engine with a high rise manifold and good (for the time) heads. My engine with smog heads and stock mid 70s vintage intake manifold was a real dog. I'd recommend going with a more modern cam design; I think the engine would be much more responsive (especially if you plan to run it on today's junk gas). Maybe I just had a bad experience, but I was very dissatisfied with this cam's performance--remember, it is a design that was state of the art over 35 years ago.
Aug 31st, 02, 05:23 AM
That's what we are saying! It need's some good CR. to really run right!
Nobody would think of dropping it in a low compression, smog engine and expect it to run right... Sorry you got a slug of a combination years ago by a shop that didn't have it together!
You want power out of a smog engine then stick with the old stock -929 cam (195/202) or step up to the Performer cam (204/214)that is just about exactly one step up the ladder!!!
Some of the guy's are even making the Crane 266 cam (210/210) work in these engines by really figuring out a good combination, but, IMHO, it is about tops for smog engines!! pdq67
Aug 31st, 02, 05:31 PM
Yeah Slow, why didnt you just tell them to build you an L79 then you get 350 hp. Some cams dont work with low compression and that is why this cam was never put in anything under 10.5-1. Man even with 11-1 you can run pump gas it bleeds of that much!!! I guess you just got burned cause I have built a handfull of these with great sucess. 12.2 in a 66 nova. thats with a 4 speed and 3.73 out back. I like to call that one hell of a engine using stock GM parts.... It has cleaned house on many a big block. I mean I could go faster but I like to say that im using all GM parts.... But im getting away from that. Im still looking for any updates on the victor vortec manifold. From what ive seen 7 HP on top aint worth 30 FT/lbs down low. Any of you guys heard anything on polishing the runners or anything. I have heard if you knock that edge out from under the exhaust valve and if you polish the runners it really helps. I just want some more opinions.
Aug 31st, 02, 06:02 PM
I was a real newbie 9 years ago (hardly an old hand now)--I will never get burned like that again, as I plan to build my own engines until I can no longer lift a wrench!
My point was a little poorly stated, but in my opinion a car that is going to see very many miles put on it should be able to run on pump gas. As everyone has agreed, the L79 cam and low compression don't work well together. Just a thought, but I would get a more modern cam with a faster ramp and keep the compression down in the range where it will run on pump gas. Of course, if you're willing to pay the extra cash for Cam2, high compression will certainly be worth more power.
Aug 31st, 02, 07:29 PM
You drop a 195hp/283 two barrel engine in a light car like a '64 to '67 Duece coupe and you would love it.
Take one crate Mr. Goodwrench 350 engine and add one Performer cam, a four barrel setup and a set of cheap headers and you can run all day on 87 octane gas AND still have a blast!!!
It won't by any stretch be a race engine, but WILL put a GRIN on your face!!!! pdq67
Aug 31st, 02, 07:35 PM
Back again. Do you ever notice that when a back-to-back cam comparo test is done, the cams are NOT the same!!
If you want to sell a cam, you pick one to test against that is not the same!!! Because if a cam is the same regardless of manufacturer it will be the same! End of story!!!
The test of the old -151 against the modern grind, case in point. You back a cam off several points of intake duration and go up in lift and sure it will beat the old -151!!!
But, I will bet a six pack of "POP" that the old -151 will live longer then the modern hi-po grind that thinks it's better! pdq67
Sep 1st, 02, 03:16 AM
The C/R needs to match the cam timing as was stated but we neglect to notice the Lo-Po heads. You can not make power without good flowing heads. Smog heads will not run. Smog intake too. Ligenfelter said something to the effect of a big cam with small heads sucks no matter what but a good set of heads with even a small cam will still run great. The heads are the most important piece of the equation IMHO.
Sep 1st, 02, 07:07 AM
pdq and stngr,
Good points! My L79 motor with smog heads and stock intake went into a '72 Buick Skylark with highway gears in it. It probably was a solid 800 pounds heavier than the old Chevy II was. Eventually I found a racer who was selling a 12 bolt rear with 4.56 posi; performance came around quite a bit with that deep gear. I think the car was actually geared too deep for the cam at that point. At any rate, I have never driven a V8 Deuce, and I'm sure you're right about even a mild mill being lots of fun in a lightweight car.
Sep 1st, 02, 06:06 PM
yeah slow you are right. Its all power to weight. Still wondering if someone can spit out the info about the victor manifold but I may just have to post again. The only time those little light cars got scarey was with a well tuned up big block. I know of some chevy II's that run a 406 wilder than any 327 I have ever built but the 327 will win out on the street cause you cant get traction with the big cubes
Sep 2nd, 02, 05:46 AM
I would stay away from the Victor Jr manifold when using the L79 cam--I think you would hurt low end torque too much. I'm not sure what kind of rev range Chevrolet rated this cam for, but Crane Cams' rating is 2200-5200 rpm (see http://www.cranecams.com/master/apps/chevy10.htm#2.%20Blueprint). If you figure that maximum power of the cam is at 5200 rpms and the Vctor Jr. manifold doesn't start making good power until 3000 rpm or more, you have really shortened the effective power band of the car. An Edelbrock Performer RPM would probably be a much better choice--maybe one of those new air gap models, they seem to make good sense.
Sep 2nd, 02, 03:09 PM
The "151" with stock 461/462 heads and 10.5-11.0:1, 4 degrees advanced, runs great and doesn't need anything more than pump premium; the factory setup ran great, but port-matching the intake and a little pocket-porting behind the valves really wakes it up. I did my last one that way, would do it again (talking stock-appearing NCRS-restored Corvettes here, not street machines). All stock GM parts (except the timing set), runs forever.
'69 Z28 Fathom Green