ZZ409 camshaft and vacuum?
Thread Starter
Joined: May 2004
Posts: 268
Likes: 13
From: NY
Car: 87 Trans Am GTA
Engine: 350 TPI
Transmission: 700R4
Axle/Gears: 3.27
ZZ409 camshaft and vacuum?
Ok, here's a wierd one. I am running the TPIS ZZ409 camshaft in my L98. How much vacuum should I be making at idle? I have it idling at 750 RPM and I'm making 20 inches of vacuum? Verified with two vacuum gauges. The cam specs were verified by a cam doctor sheet.
Cam Specs are:
287/287 Adv. Duration
226/226 Duration @ 0.050
.520/.520 lift
112LSA
Does anybody else run this cam? How much vacuum are you pulling with it?
Along with the cam, I have the following mods:
Trickflow 195 heads
Comp Cams High Energy 1.6 rockers
SLP T-RAM
Every other search I've done with this cam and vacuum came up with figures anywhere around 14-16 inches of vacuum.
Cam Specs are:
287/287 Adv. Duration
226/226 Duration @ 0.050
.520/.520 lift
112LSA
Does anybody else run this cam? How much vacuum are you pulling with it?
Along with the cam, I have the following mods:
Trickflow 195 heads
Comp Cams High Energy 1.6 rockers
SLP T-RAM
Every other search I've done with this cam and vacuum came up with figures anywhere around 14-16 inches of vacuum.
Joined: Sep 2005
Posts: 27,879
Likes: 2,431
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: ZZ409 camshaft and vacuum?
Those #s basically all pass the smell test, from lowest to highest... it's not a real huge cam or anything. In fact I'd guess 18 just looking at it but that's just me.
The farther the timing is advanced, the higher the vacuum will be (to a point); that can cause considerable variability.
The farther the timing is advanced, the higher the vacuum will be (to a point); that can cause considerable variability.
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