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Posted by: forrestkhaag May 21 2017, 12:07 PM

Does anyone know if there is a danger in running a 3.0 with tripple 40 webers with specifically 55 idle jets?

Or put another way, is there inherent danger of a too lean mixture burning a valve during the break in phase of a newly built engine / staying in the under 4K range of rpms for the first 500 or so miles.

I am being told by my slow as hell carb guru that i need 60's and that is the last thing (as of this writing) that I must have / not the 55 that it freely starts up with now....... I would kinda like to actually drive this thing again some day soon,

Any experience from you 3.0 conversion guys would be appreciated. or If you have a set of 60's I could buy, I will rush over with cash. Or a retail source in SoCal so I could drive there (in my truck........ ) with cash.....

Hopefully one of you guys has been running your 40's with 55 idle jets without issue.

As a licensed designer in multiple states, I can say from experience, Piecemeal construction blows .




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Posted by: mb911 May 21 2017, 01:48 PM

What about jet drills? Make them 60s?

Posted by: forrestkhaag May 21 2017, 02:55 PM

That is a good option seeing how rare these little things are to get ones hands on.

I will try Vision Motorsports and a few others see to see if reamers are available.

Posted by: Beach914 May 21 2017, 04:22 PM

Hi Forrest. Replied on your wtb post that you should try pierce manifolds. They have an online website you can order from. They're up in gilroy.

Posted by: '73-914kid May 21 2017, 05:05 PM

Just drive it with the 55s. If it's one step too small, it will "chuff" back up through the intakes as soon as it sees load. No real harm in going out and trying it.

Posted by: '73-914kid May 21 2017, 05:06 PM

Also, what venturi diameter?

Posted by: forrestkhaag May 21 2017, 05:12 PM

34's were the reccomended size for the 3.0. I like your attitude on the Just Do It!

Posted by: forrestkhaag May 21 2017, 05:28 PM

Guru says....... using too small of an idle jet can singe the valves...... dry the guides,... and lead to catastrophic damage on a biblical scale....... all things as we know them will end.

I will fire it up tomorrow and drive it around locally to see if the earth ends......

Posted by: PanelBilly May 21 2017, 06:13 PM

Be sure to have someone video the end of the world experience. Would be a good one for the record books. Sorry, somehow a text came thru and attached itself here. I've edited it out

Posted by: '73-914kid May 21 2017, 06:20 PM

Biblical levels of damage will occur over time I suppose.... but, these motors like a rich idle circuit, so ypull know pretty quick if it's too lean.(especially depending on camshaft grind).

You'll know it's too lean pulling away from the first stop sign.

Posted by: Steve May 21 2017, 06:44 PM

I ran 55's with my 2.7. It had a nasty mid range flat spot until I ugraged to 60.
Drive it and then check the plugs to see how lean it is running.

Posted by: rgalla9146 May 22 2017, 10:25 AM

According to Bruce Anderson (RIP) a 3.0 w/40s is good with;
34 mm venturies, F3 emulsions, 160 mains, 175 air corrections and 60 or 65 idles....maybe larger.
Can't advise you on short term use of 55s
Rory