low manifold vacuum
Thread Starter
|
Freshman User
Joined: Aug 2008
Posts: 25
Likes: 0
low manifold vacuum
I am having a problem with low manifold vacuum. My vacuum reading with engine warm and in park at 600 rpm is about 12 to 14. Problem is that I need to be at 18 to qualify to run in the mud bogs I attend.
I have a holley 600, edelbrock intake, MSD Ingnition, Fender exit headman headers (open), crane dbl roller timing chain, besides that it is a stock 351m.
Any help would be greatly appreciated.
I have a holley 600, edelbrock intake, MSD Ingnition, Fender exit headman headers (open), crane dbl roller timing chain, besides that it is a stock 351m.
Any help would be greatly appreciated.
Posting Guru
Joined: Dec 2002
Posts: 2,003
Likes: 2
From: chicago burbs
they bleed down at low oil pressure, causing the cam be "smaller" which usually improves manifold vacuum. when the rpm's and oil pressure rise,the lifter pump up fully and you're back to your full cam lift.
try setting the timing gears in the +4 setting, that should help vacuum too.
is there an rpm spec where they check your vacuum?
try setting the timing gears in the +4 setting, that should help vacuum too.
is there an rpm spec where they check your vacuum?
Thread
Thread Starter
Forum
Replies
Last Post
kermmydog
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
13
Feb 20, 2008 05:12 PM
Clifford II
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
16
Jun 1, 2004 08:21 AM
Kevin
1987 - 1996 F150 & Larger F-Series Trucks
15
Apr 14, 2000 05:23 PM
