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Old 06-23-2007, 12:41 AM
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Chevy 327 camshaft-"300" and L79

What exactly is the 1966 Chevy 327 "300" Camshaft. Is it the same as the L79? Im rebuilding a 1966 Chevy 327 and i heard the "300" horsepower cam is the best. The engine is bored 0.060" over. I have Camel-hump heads w/ 1.94/1.60 valves. I'm 14 and this is my first rebuild. Any help would be nice.
Im using flat-top Silv-O-Lite hypereutic pistons w/ two valve reliefs.

Last edited by chevyboy1993; 06-23-2007 at 04:52 PM.
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Old 06-23-2007, 01:01 AM
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L-79 Cam

The L-79 cam was the 350HP 327 cam.I have used these on several small blocks they are a great street cam.If you want a little more bang for the buck,this is available from Summit Racing part # SUM-K 1105 cam & lifters for $62.99.Read up on the posts here about cam break-in oils some oils don't have the additives they used to due to the Feds,maybe do a search on Shell Rotella.Good Luck!
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Old 06-23-2007, 05:24 AM
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Cool! good to hear another 14 year old is building an old 327. My Son built one at the same age a few years back: Dalton's Ride

We used a solid lifter cam out of the Comp's Extreme energy line, XE268S I believe and it worked well with his combination. Your piston selection, head gasket thickness, deck height, rpm range, fuel, vehicle weight, transmission, and rear end gear ratio will all play into what cam is right for you----so if you give us some more details you'll probably get some good information on cam selection.

Those Summit cams are hard to beat when you're on a budget and they've been proven to make some decent power-better than the old oem grinds.
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Old 06-23-2007, 07:15 AM
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Quote:
Originally Posted by chevyboy1993
What exactly is the 1966 Chevy 327 "300" Camshaft. Is it the same as the L79? Im rebuilding a 1966 Chevy 327 and i heard the "300" horsepower cam is the best. The engine is bored 0.060" over. I have Camel-hump heads w/ 1.94/1.60 valves. I'm 14 and this is my first rebuild. Any help would be nice.

The 300HP cam is very mild and is basically the same cam used in most 60's and 70's standard performance small blocks. Good daily driver cam for heavy cars with automatics and high gears. The L-79 as stated above is the old 327/350 HP cam. It has a bit of a lopey idle and works best in lighter cars with 4 speeds or a high stall converter and lower gears. Great "drive in cruiser" cam in a smaller engine. They are both old tech though and unless you just have to have an authentic old school cam there are hundreds of better cams. I agree on the Summit cams being a great bang for the buck. We have used a few of the 1102 and 1103 grinds and have been very happy with them. A friend has the 1103 in his '64 Impala SS with a stock 327/250 HP, PG and 3.36 gears and it works very well. Decent low end, strong mid range and pulls strong past 5,000 and even with the Glide and tall gears it pulls hard from a dead stop. No "drive in" idle though just a healthy "burble" to the exhaust note.

Last edited by Hippie; 06-23-2007 at 07:17 AM. Reason: Haven't had my coffee yet.
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Old 06-23-2007, 11:40 AM
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Cam specs on the 327/300hp cam are 195in 202ex duration @ .050" .390"in .410" ex lift @valve. 112LSA. Commonly known as the "929" cam as that was the last three numbers of the part number. As mentioned above this cam was used in most stock 350's and 400's. it's a "stock cam".

The 327-350hp "L-79" cam is 221in 221ex duration @.050" .447" .447" lift 114LSA. Commonly referred to as the "151" cam. This cam likes compression rpm and rear gear in a 327. Needs 10:1+cr and 4.10's. A 2800/3000stall converter helps too. This cam was origionally used with a 4 speed man trans in 327 L-79 Chevy II's and Corvettes.

If you'll be using a stock 2000 stall converter, maybe a little less actual compression (9.5) and more modest gearing (3.08 to 3.55) I would suggest a aftermarket hyd cam that falls somewhere in the middle of these two factory cams. Something like a Crane H272-2 Grind #113942
Or a Comp Cams Dual Energy cam 265DEH #12-208-2

Either of these modern cams will make more torque and probabily more power as well than the old "151" cam if you'd like a "better street cam" for your 327 build.
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Old 06-23-2007, 11:54 AM
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Since both cams indeed do work, but are based on old technology, I`d use something else, even so to each his own. The summit cams are okay also. But if your looking for a cam with a lopey idle, but still has excellant street manners than the the comp 268H magnum is for you, it`s a rather small cam, has great low and mid range power, will work with a stock converter. If I recall correctly the specs are .218 Duration @.050 and .454 lift. Since your 327 is a smaller cubic incher than a 350, and you wanted to feel safer with the low end, you could advance the cam 4 degrees at the timing chain. My hats off to you for building a 327, these are great small blocks, give it some gears and tune it accordingly, and it`ll surprise a few 350`s.
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Old 06-23-2007, 12:03 PM
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Quote:
Originally Posted by DoubleVision
Since both cams indeed do work, but are based on old technology, I`d use something else, even so to each his own. The summit cams are okay also. But if your looking for a cam with a lopey idle, but still has excellant street manners than the the comp 268H magnum is for you, it`s a rather small cam, has great low and mid range power, will work with a stock converter. If I recall correctly the specs are .218 Duration @.050 and .454 lift. Since your 327 is a smaller cubic incher than a 350, and you wanted to feel safer with the low end, you could advance the cam 4 degrees at the timing chain. My hats off to you for building a 327, these are great small blocks, give it some gears and tune it accordingly, and it`ll surprise a few 350`s.
The comp cams CS 268H-10 Pn# 12-210-2 is already advanced 4 degrees. This 4degrees of advance is ground into the cam when its made. (106deg intake C/L) Most of the mild/moderate comp cams are made like this with 4 degrees of advance dialed in. Only the biggy sized Magnums like the 305H and 306F are made (straight up).
The comp H268-10 will work fine with 9.5:1, some rear gearing (3.55-4.10) and a mild stall increase (2500-2800) over stock. the stock converter is 12". You'd want a 11" converter for this one. It's another good cam choice.

Last edited by F-BIRD'88; 06-23-2007 at 01:34 PM.
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Old 06-23-2007, 12:09 PM
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Yes Bird I was aware of the 4 degree advance ground in, however, It can still be advanced more and likely isn`t going to really hurt anything. No harm no foul here, but I was just recommending a cam of my opinion that would give good street manners and still lope, I wasn`t going to get technical about it. Like I`d already said dude, to each his own.
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Old 06-23-2007, 12:54 PM
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That 4* of ground in advance on the cam is to compensate for the 4* of retard ground into most modern crank shafts.

The 327 crank will not have this retard so installing the cam essentially advances the cam. I have seen numerous 327's built with the L79 cam using headers, dual plane intake, vacuum secondary carbs with 3:42 or 3:73 gears get 15 mph around town, and 19+ on the highway in early camaros.

It is a forgiving cam. Using any 268 type cam from any mfgr will be just about the same, only the ramps sometimes need better springs.
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Old 06-23-2007, 01:24 PM
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There is no such thing as a crankshaft made or ground with 4 degrees of retard.
The camshaft valve timing is phased relative to the crankshaft. Not the other way around.
Most aftermarket hi performance hyd cams are manufactured so that when the timing marks on a standard matched timing gear set are aligned during installation, the cam dowel pin is positioned so that the cam timing will be slightly advanced from (straight up) usually 4 to 5degrees.
This slight bit of predialed in valve timing advance enhances low mid range torque, overall performance and allows for some timing chain wear over the life of the timing set. (as the timing chain wears and gets slack the cam timing retards in a running motor)
During the mid 70's 80's "smog era" GM took the same stock GM cams from the 60's V8 motors and changed the camshaft dowel pin location to dial in some valve timing retard to lower emissions. The timing gear set did not change The crank did not change. The crank keyway did not change.
Same old stock cams, same old cranks, same timing sets. Different GM part number, different camshaft dowel pin location. No retarded cranks.

eg: most comp cams hi- energy, dual energy, magnum and Extreme Energy cams are ground on 110 LSA. When installed with the timing gears dots aligned they will be 4 degrees advanced in the motor . intake on 106 C/L ex on 114 C/L.
Crane cams and most of the others are the same 4 to 5deg of advance dialed in to the cam when its made.
Do not mix timing gears, they are a matched set. If you mix the top and bottom gears from different sets or manufacturers you will get cam timing errors.
Ford and Chrysler used various other methods to move the camshaft timing around to enhance emissions.
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Old 06-23-2007, 01:30 PM
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[QUOTE=F-BIRD'88]

There is no such thing as a crankshaft made or ground with 4 degrees of retard.

[QUOTE]

You obviously have never taken a steel 350 crank from a 69 or 70 model engine and placed it side by side with a cast smog motor crank and seen the difference of where the key way was ground. That was how the crank was retarded the cam 4* with no other mods.

I had instructions from both Crane and Comp Cams about this very retarded key way when installing cams in the 80's. I usually put the cam up 4* using the slot on the crank sprocket and got a 2* advance out of it.
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Old 06-23-2007, 02:02 PM
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"You obviously have never taken a steel 350 crank from a 69 or 70 model engine and placed it side by side with a cast smog motor crank and seen the difference of where the key way was ground. That was how the crank was retarded the cam 4* with no other mods."

You cannot compare the relative crank snout keyway positions of a GM cast crank and GM forged crank just by looking at them layed out side by side on a table.. the counterweights are different. If you were to set the cranks up to appear aligned to each other visually , the crank rod throws will not be exactly aligned. therefore the keyway appears to be in a different spot. You would have to install both cranks in a motor and using TDC of #1 piston as a reference, compare the relative position of the crank keyway, to the rod throws, no the crank counterweights. I think you'll find them to be the same.

Its very possible thou unlikely in most cases, to get a combined, stacked total error of 6 degrees on an assembled motor. Most of the time things work out to within 2 degrees When the parts that make up the posssible stacked error are manufactured to tolerance.
This possible combined error is why they make degree wheels for checking actual valve timing.
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Old 03-31-2013, 05:36 PM
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327 cam

I have a problem . I've built sbc for years and never saw this . I have a (300) HP 327 in a '75 Monza with a Super T-10 and a 12 bolt rear . I'm retired and needed a toy for the strip . I installed a Comp cam, intake .500 and ex .488 and when turn it by hand it locks up when the ex gets close to max lift . I've use cams bigger than this in a 350 and 370 HP block but those had dome pistons . And maybe deeper valve cuts ? This has flattops with 4 eyebrows . Could it be that with this piston my limits are less ? The factory listed the 300 cam lift at about .360 ? If I can't use it, I was thinking of installing a .390/.410 . I just wanted a little more power and the latest cams are better . These Pro Comp alum heads have a 64 CC chamber but I don't see where that should hurt . The chamber is cocked a little compared to stock, and I wonder if the ex is hitting the side of the chamber . They weren't designed for a '68 engine . I hate to pull the heads but I'd rather change cams . I'm not going to cut the pistons . Too much work . Let me know what you think . Thanks .
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Old 03-31-2013, 05:47 PM
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Jet...... non stock parts combos require that you check VTP clearance.

Start by degreeing the cam to ensure it is timed correctly then clay the pistons for VTP clearance.
Look for Valvetrain stack up too..

clairify what cam this is...

durations bigger than 244@.050 must be checked for clearance.
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Old 04-01-2013, 10:59 AM
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The L79 is a great cam with great street manners. This is the Crane Vintage Muscle version.




331 CI, pump-friendly 9.5:1 CR
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Holley 600 dp, choke horn milled and blended, Primary - 69, Secondary 74, Squirters - 21
1/2" Aluminum open spacer port matched to manifold, exterior polished
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Camel hump 1.94/1.50 heads hogged out to 2.02/1.60, pocket ported, port matched, pump-friendly hardened seats, 3-angle valve job
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Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
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