what vacuum do you get with your cam

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Dec 13, 2004 | 10:35 PM

cormyr

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Joined: Apr 2003

Posts: 338

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From: Maine

Car: 89 Formula 350 WS6

Engine: 383 miniram

Transmission: 700R4

what vacuum do you get with your cam

just wondering what actual vacuum to expect with a more aggressive cam. id appreciate knowing what anybody else has found and at what idle rpm too.

Dec 14, 2004 | 01:22 PM

jbenge

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Joined: Sep 1999

Posts: 1,496

Likes: 60

From: Danville, IN

Car: 1991 Camaro Z28

Engine: LS1

Transmission: 4L60E

Axle/Gears: Strange 12 Bolt, 3.42

Every engine will respond differently to cam changes..... dispacement, compression ratio, and cam choice all play a big role in how much vacuum the engine will make at idle.
See my signature for details of my engine..383 w/10.2:1 compression. My current setup has about 10in of vacuum at idle (800rpm) with comp hyd/roller (242/248 dur @.05, .540/.560 lift). My old cam was a bullit hyd/roller (225/230 dur. @.05, .525 lift). It made about 13-14in of vacuum at 750rpm. Hopefully that info helps.

Dec 14, 2004 | 05:46 PM

nsimmons

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Joined: Jul 2001

Posts: 616

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From: Langley, BC, Canada

15"s with a summit 1103, in sig
800rpm idle

Dec 14, 2004 | 06:37 PM

FbodTrek

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Joined: Oct 2003

Posts: 1,668

Likes: 1

From: Houston

Car: 86 Berlinetta 84 MonteCL

Engine: 3.4 MPFI 3.8 229

Transmission: 700r4 T350

17 in/hg. 3.4 liters, sucking through a soda straw. Wonder what would happen if I had a better intake manifold.....

Dec 14, 2004 | 08:34 PM

IHI

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Posts: 4,671

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From: Waterloo, Iowa

Car: 86 firebird with 98 firebird interi

Engine: pump gas 427sbc Dart Lil M 13.5:1

Transmission: Oldani TH400 w/ BTE 9" convertor

Axle/Gears: 31 spline Moser/full spool/4.11Rich

Mine pulls 15" at idle and I did install a vac can before taking down the road "just to be sure" this set-up I have now is teh best brakes the cars every had even when it was a stocker with 4 factory disc brakes.