427 Cam specs
Melting Slicks
Joined: Aug 2001
Posts: 2,501
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Re: 427 Cam specs (LeAnn82Collector)
LeAnn, I'm surprised SWCDuke and/or JohnZ haven't jumped in to help here. I'll post to bring you up to the top of the threads again and hopefully someone will answer for you.
Race Director
Joined: May 2000
Posts: 12,712
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Re: 427 Cam specs (clem zahrobsky)
My interest and research is focused on SBs, and I've never studied the BB cams in any detail. I believe specs are listed for the L-68 hydraulic cam in the Chevrolet Power Manual, but they appear to be the typical Chevrolet published specs that pick timing points at some unspecified level above the base circle, so they are pretty much meaningless for use to compare with other available cams.
Duke
Duke
Emerging Vendor
Joined: Mar 1999
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From: San Diego CA
Re: 427 Cam specs (clem zahrobsky)
I posted by accident under my wife's login. The cam specs I'm looking for are for the 69 427-400 engine. Same cam as the 390 horse. I'm more familiar with the small blocks, so I appreciate any help.
Greg
Greg
Team Owner
Joined: Oct 2000
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From: Washington Michigan
Re: 427 Cam specs (corvgreg)
Can't give you comparative duration figures, as Chevrolet publishes them at .008" lift, which are meaningless. Lobe lift is .2714", gross lift with 1.7:1 rockers is .461". Cam is P/N 3883986 ('66 & '69) or 3904364 ('67 & '68).
Race Director
Joined: May 2000
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Re: 427 Cam specs (JohnZ)
John - most "advertised" specs published in cam grinders catalogs are taken at .006" valve lift using the "theoretical" rocker ratio, so post what you've got.
I've never understood how Chevrolet specs hydraulic cams. For example, Corvette News back in '65 lists inlet duration for the L-79 cam as 342*. The Chevrolet Power Manual says 320*. It's actual duration at .006" valve lift is about 270.
DD2000 seems to work best with the .006" valve lift timing numbers.
Duke
I've never understood how Chevrolet specs hydraulic cams. For example, Corvette News back in '65 lists inlet duration for the L-79 cam as 342*. The Chevrolet Power Manual says 320*. It's actual duration at .006" valve lift is about 270.
DD2000 seems to work best with the .006" valve lift timing numbers.
Duke
Safety Car
Joined: Jan 2001
Posts: 4,414
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From: Barrington IL
Re: 427 Cam specs (SWCDuke)
I also would like to know why Chevy used 2inch exhausts in 69. My guess would be that they figured any hotrodder would just replace the stock system with a freer flowing exhaust system ie. headers and either side pipes or larger under car ones.
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Verdad Gallardo
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From: delmont pa
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Re: 427 Cam specs (LeAnn82Collector)
3883986 cam lift .461 IN/.480EX specs at .050 lift, dur, 214IN/218EX, IO -3 degrees, IC 37 degrees, EO 49 degrees EC - 11 degrees, lobe sep 115 :chevy
[Modified by clem zahrobsky, 8:03 PM 11/21/2002]
[Modified by clem zahrobsky, 8:03 PM 11/21/2002]
