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Re: Holley 390 Secondary Fuel Metering

To: zwissler@hsonline.net
Subject: Re: Holley 390 Secondary Fuel Metering
From: Ian Crocker <ian@btcase.bt.co.uk>
Date: Mon, 27 Sep 1999 11:02:40 +0100 (BST)
> I'm running a TR8, Offy/JWR Dual Port manifold, Isky mild cam, Silv-o-lite
> +.040, 9.5:1 pistons, headers, Mallory Unilite w/10 degrees static advance
> and 24 degrees centrifugal-only advance.  I'm using the Holley 390 for
> carburetion with primary jets two sizes up from stock, and the
> non-adjustable secondaries.  Generally use 93 octane premium from one of the
> "name brand" stations.
> 
> My problem is that on WOT acceleration in 3rd  and higher gears I start to
> get heavy pinging starting at about 3500 rpm and continuing to redline.  I
> don't get knock anywhere else or under part throttle acceleration.  

Your engine spec is very similair to one that I had on a 390.  I am sure
that your problem is weak mixture because a standard 390 has 51/53 primary
and secondary jets.  My car required 56/65s.  The jetting was established
on a proper engine dyno and then checked on a set of rollers.  The engine
spec was 9.75:1 pistons, flowed heads on std valve, 218 cam, headers putting
out about 210-215HP.

Also, 3500 is roughly where the secondaries start to open (depending on
what spring you have installed).

Regards,

Ian
-- 
"I think that it is much more likely that the reports of flying saucers
are the results of the known irrational characteristics of terrestrial
intelligence than of the unknown rational efforts of extra-terrestrial
intelligence"  --  Richard P Feynman.

Ian Crocker    ian@btcase.bt.co.uk    http://www.geocities.com/MotorCity/9190/

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