PYasher

Any recomendations on the best cam shaft to buy for a 327 -350 HP.
Anyone know the specifications for the stock cam - lift and duration?
Thanks
Perry

ghostrider20

Are you looking for a solid or hyd. Cam.

If it were me, I would go with the solid lifter LT1 cam.
From DD2K, solid cams make about 20 more HP then their Hyd counterparts.

Here are the specs for the various GM cams (Duke Willams).

050" lifter rise specs:

962: 224/224. 114/114. 114, .447/.447

151: 221/221 110/118, 114, .450/.460

178: 231/239, 110/122, 116, .441/.455 (LT-1 cam)

SWCDuke

It's tough to beat OE cams on torque bandwidth. Most aftemarket cams have too much overlap, which will hurt low end torque if you run the OE type manifolds.

The L-79 cam is excellent. The only "upgrade" I would consider is the mechanical lifter LT-1 cam. It will make a little more top end power with only slight loss of low end torque, and it can be revved safely to 6500 versus 6000 for the L-79 hydraulic cam.

By far the biggest difference is head work. The L-79 cam with pocket ported/port matched heads with a multiangle valve job with make more power than the LT-1 cam with stock heads, and this head work will not hurt low end torque in either case.

Duke

toddalin

The Crane Vintage Muscle 327/350hp cam is a really nice choice (151) and with proper manifold, head work, and headers can put about 300 hp to the ground.

222 degrees @ 0.05, 0.447" lift

Dave McDufford

Actually some "old guy" out in southern California told me the head work could cause a slight reduction low end power because the reduced turbulence in the air stream resulted in poorer fuel atomization (or fuel/air mixing).

I remembered that because I thought that it was an interesting phenomenon.

Dave


sorry Duke...

SWCDuke

Depends! If you do a full "race port" job and open up the entire passage low rev port velocity will be lower, which could yield poorer fuel vaporization.

Pocket porting/port matching just addresses the valve seat/bowl area and port inlet. Rather than substantially increasing average port area, which lowers velocity, pocket porting/port matching improves flow efficiency.

Pocket porting/port matching may have a slight negative effect on low end torque or mixture quality, but in the worst case it should only be slight and not have a signficant impact on low speed operating characteristics.

Duke

grumpy55

Is the L-79 cam the "151" ?

Donny Brass

yes it is

grumpy55

Thank-you, then what is the "962" cam ?

SWCDuke

'69-'79 L-46 and L-82

Duke

1965L76

Duke, if you were going with a hydraulic cam would you recommend the L79 or the L82/48 cam? What would the difference be between a solid lifter cam with the same characteristics as a hydraulic cam?

ghostrider20

Solid cam vs HYD.

About 20-25 HP and 1000 RPM.

Mark

SWCDuke

Note that the 962 cam has just marginally longer duration than the 151, but is effectively retarded four degrees. This is because it was designed for the longer stroke 350. As stroke increases you can have a later closing inlet valve for high peak power and still have adequate low end torque.

I think the 151 is close to the ideal hydraulic cam for a high performance street 327, but if you chose to go with the 962 I would advance it four degrees to get the same centerlines as the 151.

It's tough to compare hydraulic with mechanical lifter cams because none that I know of have the same basic specs. Probably the biggest advantage of mechanical lifter cams is that they offer an extended usable rev range. With a little head work the LT-1 cam will make peak power on the 327 at about 6500 and useable power to about 7000. The same engine configuration with the 151 cam will make peak power at 6000 or a little above. The 962 cam installed with the OE 350 centerlines in the same 327 will probably suffer lifter pump up while the power was still rising somewhere in the range of 6000 to 6500.



Duke

PYasher

All,
Thanks for the advice.
I will be going with the 151 cam
I have completed a body off and intend to drive the car.
Due to physical limitations on my part I had to build an automatic (Bowtie overdrive 700R4) car and desire low end torque.
Do you have a recomendation as to where to purchase the cam from?

Again - thanks for all the great advice

tapio

Check Summit Racing @ www.summitracing.com

Part # CRN-967601

Hope this helps.

JohnZ

Having an automatic changes the equation - you need low-end torque with an automatic, and the "151" cam isn't a great choice (it was never available with an automatic). For your application, I'd recommend the stock "929" (300hp) cam - it makes gobs of low-end torque, just what you need with an automatic.

SWCDuke

John is basically correct, but since the 700R4 has a 3.06:1 first gear the L-79's relatively less low end torque will be somewhat masked. The L-82 was available with THM (2.48:1 first gear), but the tallest available axle was 3.55.

It comes down to where you want the power. The "929" 300 HP cam will be stronger up to about 3500 and the L-79 cam will be stronger above this range.

Both cams are available from Federal Mogul. GMPP also offers some vintage cams, which are made by Crane, and Crane and some other aftermarket cam grinders offer them.

Duke

toddalin

So you can get an idea of the torque curve with the 151 cam, I've included my combination and dyno sheet. It makes a lot of ZZ3 and ZZ4's look pathetic by comparison.

331 CI, pump-friendly 9.5:1 CR
K&N 14"x4" air filter, Corvette drop base and lid
Holley 600 dp, choke horn milled, polished
1/2" Aluminum open spacer port matched to manifold, exterior polished
Edelbrock Performer RPM, port matched, exterior polished with all extraneous castings and lettering removed
Homemade lifter valley splash shield to keep hot oil off manifold bottom
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
Comp Cams 1.52:1 roller-tip rockers
Crane Cam Vintage Muscle 327/350 hp cam, 222 degrees @ 0.05, 0.447" lift (with 1.50 rockers)
Doug Thorley headers, dechromed and ceramic-coated
2.5" mandral-bent exhaust (including tips), 2" cross-over just before rear axle
DynoMax stainless Ultra Flow mufflers
Mallory Hyfire IV CD ignition box triggered off Accel points
Mallory high voltage chrome coil
Mallory spiral-wound coil wire
Mallory solid copper plug wires, ends soldered to wires
Champion plugs
37 degrees total ignition advance
Carter high volume fuel pump
Melling high volume oil pump
Open breathers
Polished aluminum high flow water pump
Flex fan with polished aluminum spacer
Polished aluminum one-wire 100 amp alternator
Muncie M-20 CR 4-speed
Hurst shifter
3.70:1 positraction
225/60/15 Firestone Firehawk SZ50s on 7”-wide Western 30-spoke Turbine Wheels

At the time of the dyno pull, the engine had never been professionally tuned up. Car did 293 ft-lb and 293 hp @ 5,500 rpm on the chassis dyno. Engine pulls to 6,200 rpm and does over 200 ft-lb from 1,900 rpm. This was prior to a LARS TUNE-UP and some clean-up work around the junction of the carburetor and base of the air cleaner that smooths the flow through this area and should be good for a few ponies. Car has run 107 mph in the high 13's (old, bad tires) at the quarter. Car is extremely streetable and could probably even run 87 octane if it had to. (I can't get the engine to ping no matter how far I advance the ignition.)

The secret to power is in the attention to details!

SWCDuke

Excellent mid and upper range, but the bottom end is soggy. It's tough to tell because of where the pull began, but it looks like the engine is not making 80 percent peak torque by 2000, which is my basic criterion for a street engine - ESPECIALLY with an automatic transmission, but 1500 would be best with a typical OE stall speed and axle gearing - 2000 is okay with SHP gearing and a four-speed.

I always pull from 1000-1500 so I see the entire torque curve. We actually do use revs that low. Last summer I did two pulls on my Cosworth Vega from 1000-7000, and the torque bandwidth was 1900 to an estimated 7200.

Dave McDufford's blueprinted L-79 w/ LT-1 cam made 80 percent at only 1600 on a lab dyno, but it didn't begin to rise much until about 2500.

Most dyno shops pull from 3000-3500, so you never know what's going on at the bottom end, which is where we spend most of our time driving, but I've been trying to educate Darryl at R&D.

Duke

toddalin

I could be sacrificing a little low end torque to the open spacer plate hopefully helping top end breathing.