L79 cam questions
 

My 350/327 CE short block i bought from Chev in 1976 had an L46 cam installed as the current replacement.

i hear from people on this forum that the L79 was really a better cam.

i thought the L46 cam was fine, but it was happiest above 3000 RPM.

How is the L79 cam for cruise at say 2000 RPM? Same motor.

Too much overlap? What about cruise fuel economy at that RPM.

Trans will be most likely, a 700 R4 trans, 27-28" tall tires, 3.3-ish rear axle, 1937 Ford truck, which I don't think will weight very much.

If any body has other cams selections, I would eb happy to hear them. I am not going drag racing, but want some get up and go, and reasonable fuel economy

Thanks,
Doug

I have run both. Performance wise, the L-79 cam is similar in characteristics to the 097 cam but it runs out at close to 6K. Pulls good all the way there though including the low end.

The L-48 cam probably has more low end but performance wise, is a small step above the 300 hp cam. It runs out of breath past 52-5300. My experience anyway. I wouldn't put one in a performance engine if it was free.

I can't comment on your gearing. I've never run anything that high with a cam.

of the 2 cams, you would like L79 cam better

The truck will weight in somewhere between 2700 and 2900 pounds wet, i believe.

The 700R4 has a 3.06 first gear, so with 28" tall tires, and a .350 gear, it should be OK on off the line accel.

The fuel econ at a 2000 RPM cruise is a concern, as the .70 OD top gear on the trans will drop me to 2200 RPM at 75 MPH and 1764 RPM at 60 MPH with a 28" tall tire. I don't want an L79 cam pushing all the fuel right out the exhaust at lower RPM.

Doug

I missed the '37 Ford truck part and the weight. The cam should pull fine with those gears.

If you want to maximize your fuel economy, I don't think either cam is best choice. If you want something that runs good, good mid range, good economy, go for the L-79.

True, but then i would have to go with different pistons for a lower CR, most likely. I don't want to rebuild the entire motor.

Not building a race car, just something that has some zip to it.

Probably go with block hugger headers and most likely, an Edlebrock Air gap performer manifold. The advertised 5500 RPM max range will probably be a bit higher due to the smaller 327 vs a 350. A Holley 6210 650 CFM spread bore, will also improve low RPM drivability, as I had a similar combo on this motor once in my Corvette, and it was a real zippy little car.

Doug

Also, where do I get an L79 cam these days? Someone must make a duplicate that hasn't been tweaked.

Thanks,
Doug

The L-46 cam is slightly larger than the L-79 cam while the L-48 cam is much smaller than either. As I recall, the L-46 (350hp 350) cam was 224º/224º, .450/.450 vs 222º/222º, .447/.447 for the L-79 cam. I don't think there'd be enough difference between them to worry about.

L79 cam source
 

Doug:

from my notes the Federal Mogul Sealed Power cam # CS179R is the aftermarket version of the OEM 3863151 L79 350hp hydraulic cam.

Mike

Comp Cams supposedly has a version of the L79 that's improved over the original:

http://www.compperformancegroupstore...ory_Code=HFTNP

Close: The L-46 (6962) cam has .450/.461 lift (with 1.5 rockers) 224/224 deg. and I considered it a dog when used in the lower compression engines later in the 70's. It was a good runner in the higher compression 350's of 69/70. Lobe separation of 114.5 deg.

Interesting that my EA 3.2 shows the 3151 cam as being 4 deg. advanced, while the 6962 cam being .5 deg. retarded.

Plasticman

Seems kinda long in the duration for a 327 motor. But the advertised duration is similar to the original, or maybe even a tad less, the .050" duration is much longer, obviously a more aggressive lift ramp. Maybe it won't be that bad.

Thanks,
Doug

I tried that Camquest program, and came up with a hyd roller XR270HR that looks interesting, the stock piston reliefs will clear the .495/.504 lift based on a similar lift Crower cam i had in there once.

Doug

I know the L79 woke my 84 up in its 350 with no other changes. Car was so damn slow it was embarrassing to drive.....and I Didi`t want to experiment with cams...I would recommend it to anyone wanting a hydraulic cam up grade.

Take a look at the ZZ4 crate motor cam. The 151 cam was the basis for those developed for the ZZ series motors.

Harry

You want the Crane Cams Vintage Muscle Grind #3863151. Crane no longer seems to offer this exact grind (they have very close grinds though), but using the grind number you can come up with a cam with identical specs, such as these on the 'bay:

http://cgi.ebay.com/ebaymotors/Chevy...Q5fAccessories

http://cgi.ebay.com/ebaymotors/COMP-...Q5fAccessories

http://cgi.ebay.com/ebaymotors/SMALL...Q5fCarQ5fParts

The L79 cam is within 2 degrees of duration of the L46/L82 cams at the same 114 degree lobe separation angle. However, the biggest difference is that the L79 cam is 4 degrees advanced from the 0 advance on the L46/L82 cam (p/n ...6962)

Although the latter cam has .003 to .013" more lift, this difference is insignificant. If you already have the 6962 cam, just advance it 4 degrees and it will perform just like the L79 cam.
:thumbs:

:iagree:

Advance the L46/L82 cam 4-degrees, and with reasonable (10:1 or more) compression it will run with the L79/350hp cam.

The 4-degree retard on the L46 cam allowed it to run with lower compression & emissions, but it also moved the usable powerband up to give the driver a weak impression of "getting on the cam" (something people wanted since the 30-30 was dropped). Unfortunately this left a hole in the low rpm power response (but it felt good climbing out of that hole).

When working with 210hp and 8.5:1 CR the L46 was good, but it's much better with 10:1 and the advance put into the cam to restore the lost power in the lower rpm range. If you were running the L46 straight up and are concerned with the late power (the weakness below 3000 rpm), running it advanced 4-degrees or enough to achieve closer to 7.5:1 to 8:1 DCR will help a lot.

:cheers:

First gear will jump with that combo. I am running a wide ratio Muncie with 3.55 gears which all around I like. I switched to the "151" cam years ago and am very happy with it. If the rpm is to low at 60 just don't use the OD until you are running at a higher speed.

I think I am going with the hyd roller.

Duration at .050" is 218/224, IIRC, advertised is 268-270ish, but .495"/.502" lift.

EA gives this cam gobs more power/torque (think 40 HP and 30 ft-lbs peak, about 12HP, 14ft-lb average) between 3-6K RPM than an L79, with no loss in bottom end torque.

Doug