1965 30-30 versus LT1 cam

[Joe C.]

Re: 1965 3030 verces LT1 cam

In your earlier post, you were saying that you can tell the difference between a Duntov and LT-1 cam. I countered by saying they both idle at 900@12", so how can you tell? I'm still waiting for your answer.

Now you are saying the the LT-1 cam idles different than the 30-30. Well, yeah, it only pulls 10" at 900.

The second guy who built a "327 LT-1" from a '65 L-76 was also worried about that.

His final comment on the subject after several months driving the Beast is that he can't tell the difference in idle, but the engine has gobs more low end torque with more top end power and revs (I had to beg him to keep it to 7000 because the power curve shows what appears to be a little valve float at 7250.), which is more a function of the head massaging than the cam - regardless of whether the cam is a 30-30 or LT-1.

Duke

Well Clupper responded to a 4 year old post as if it were yesterday, so I might as well follow-on.

How can you tell the difference between an 097 and a LT1 cam other than idle vacuum difference? They only differ by 8 degrees in overlap, so only a VERY seasoned judge would be able to detect the difference in that aspect. The LT1 (if lashed according to the factory specs of 0.030" on the exhaust side) will produce a cacophony of clackety-clack tappet noise versus the much quieter valve train noise of the more efficient (.012/.012 and .008/.012 for some 283s) 097 cam.

[Jason S.]

Re: 1965 3030 verces LT1 cam

The 097 is too small. It DOES however, have nice short (efficient) clearance ramps, which is why I always recommend using it on a 327 with 1.6:1 rocker arms

The 346 is too big. Well, not really too big but EXTREMELY inefficient with its humongous clearance ramps

The LT1 is "just right". It does, however use the inefficient 30-30 lobe on the exhaust side, with a much better designed intake lobe

FYI - A couple interesting articles pertaining to our kind of discussion. The main downside to the online articles is that I can't find any of the HP/TQ overlays in graph form. Their "results" are just stated in the sidebars next to the pictures as you scroll through the slideshow. Their purposes were to compare L76 vs LT1 vs DZ302, so engine displacement is a factor in addition to cam specs. I'd love to see such a cam shootout on the same engine - EITHER a 327 or a 350 - if anyone has seen one in the past, please pass it along.

Let me know what your thoughts are on these links - entertaining reading, at least:

Solid Lifter Cam Testing:

http://www.superchevy.com/how-to/project-cars/sucp-0909-chevy-small-block-testing/

Hydraulic cam Testing:

http://www.superchevy.com/how-to/engines-drivetrain/sucp-1003-classic-chevy-small-block-dyno-testing/

And while not directly related to our discussion, a Ford vs Chevy shootout for good measure :
Small Block Shootout - Ford vs chevy - L76/DZ302/LT1 Testing:

http://www.hotrod.com/how-to/engine/hrdp-1001-muscle-car-engine-shootout/

[Jason S.]

Re: 1965 3030 verces LT1 cam

And for those that may not already know this - I have found which Cam manufacturers out there are still making reproduction grinds:

Crane Cams makes actual reproductions of Factory Cams:
Makes the 365hp L76/DZ302 as well as the 340hp "097" cam, but I saw no LT1:
http://www.cranecams.com/72-77.pdf

SpeedPro Cams makes actual reproductions of Factory Cams:
They list an LT1 equivalent (CS1145R), L76 "30-30" equivalent (CS188R), and ??"097" equivalent (CS113R)?? - double check me on the 097.

http://fme-cat.com/PerfApplication.aspx?brand=SPEED-PRO&engineMF=Chevrolet&engineFAM=Small%20Block&prodCat=Camshafts&subCat=Camshafts&partType=Mechanical&disp=283,%20302,%20305,%20327,%20350,%20400%20Engines&ga=Y

Comp Cams "Factory Muscle" Cams:
They list the 365hp "30-30" L76, DZ302 AND LT1 as the same specs…..but the LT1 did differ from the L76/DZ302 we know this………………..
http://www.compcams.com/Company/CC/c...px?csid=3&sb=2

Comp Cams "Nostalgia Plus" Hydraulic, "Improved" versions of older factory cams:
They claim they have studied the "30-30" L76 and have made a more "modern" hydraulic improvement:
http://www.compcams.com/Company/CC/c...?csid=111&sb=2