Holley Help

General Chat About Exhaust, Cylinder Heads, Fuel Systems And Intake

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simontwithers
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Joined: Thu Jul 31, 2008 9:44 pm
Location: Leicester UK

Post by simontwithers »

Update, after buying an innovate wide band afr gauge i have learnt alot about jetting. I cannot recommend it enough to get fueling right. For example, when working blind, i found going much richer made my v8 feel stronger so i kept going richer. When in fact all i was doing was jetting the primaries so rich that they would cover the whole rev range without the secondaries. As soon as i plugged the afr in i knew exactly where i was rich ( everywhere) and rejetted. My v8 now pulls even better and is 'good' on fuel too!

I have updated the rest of this post with my current jetting for reference.


For all those that come across this post using the search engine in the future........


The solution for me this time was jetting.

By jetting up a couple of sizes a I now have a V8 which pulls strongly.

I previously thought I had disproved jetting by pulling the choke on under load (richening up), but this theory did not work.

I have now jetted up to 52 on the primary main jets and 54 on the secondaries. I removed a bog off idle with a larger accelerator nozzle and cam.

To change the secondary main jetting on the vac secondary carb, you have to buy the conversion kit which i bought from Real Steel.

I hope this helps someone in the future.

And thank you to all those who gave helpful suggestions this time.

Kind regards

Simon

For reference:

My engine is a 3.5 SD1 9.35:1
Mild Kent (200) cam
Stage 1 heads
Holley list 8007 model 4160 carb on Offy 360 manifold
range rover matched cast manifolds with 2" down pipes down to 2.5" single straight through exit with large cherry bombs.
Last edited by simontwithers on Wed Jun 22, 2011 8:56 pm, edited 2 times in total.


There's no turning back now, I've finished being nice with this engine.

mgbv8
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Post by mgbv8 »

Thats great news Simon!
And thanks for posting up the settings mate. Thats more info for the data bank.

Regards
Perry

Perry Stephenson

MGB GT + Rover V8

9.62 @ 137.37mph

Now looking for 8 seconds with a SBC engine

http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw



https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw

Big Drak
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Joined: Fri Feb 23, 2018 5:53 pm

Re: Holley Help

Post by Big Drak »

Hi Perry,
I know i am a bit late to the party :-) but have only just come across this old post and am interested in what you said about setting up a holley with the pv blocked off and same jetting on all 4 corners.
i have an old tvr wedge with a later 4.0 tvr engine but efi deleted and edelbrock performer manifold installed, i did have an edelbrock performer 500cfm carb fitted but could never get it right. have just recently fitted a rare holley 390 double pumper that i found used on ebay. i stripped and cleaned it and set the float needles and seats and fitted it just as it was with the jets it came with as i have no other holley jets, but thought i would just take a chance and give it a go, and even though it was jetted for something else, it ran better than i ever managed to get the edelbrock.
i was particularly attracted to it being the small cfm 390 but the all mechanical dp style carb rather than vac secondaries.
it is list 6895 and currently on primary main jet 51
secondary main jet 68
power valve 5.0hg
accelerator pump white cam hole one 30
the rest of the set up is mallory unilite dizzy and msd 6a cdi
i have no afr gauge and have so far only ever done seat of pants dyno and tuning.
i have set ignition to 14 at idle and 34 all in by reducing mech timing from 24 to 20 and have set vac for an extra 10 degrees. the carb has no vac ports at all being a competition carb but i have plugged the dizzi into full manifold vac by t-ing off the brake servo port in the manifold.
so i am wondering if you think the type of tuning you described might be good for my dp carb or is only suitable for the vac secondary type. i'm new to holleys, the car goes well so far but only done a couple of quick drives round the neighbourhood so don't know what it is like at high speed yet, great fun at low speed so far, amazingly with this comp carb the car is very civilised round town, starts very easily, idles nicely and pulls well from low revs and takes off when you stamp on the gas. any tips would be much appreciated as you really sound like you know your stuff with holleys.
here is a clip of the car running when i first fitted the carb, cheers, Drak (North London)



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