start jetting 406cui 18 degree engine

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hjallle123
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start jetting 406cui 18 degree engine

Post by hjallle123 » Wed Oct 11, 2017 4:20 pm

Hi

what jettings to start with on a 406 cui sbc
dart block
borr 4.125
stroke 3.80
heads 18 C brodix cnc ported 2.18 intake valve 1.625 exh valve
comp 15.8
cam bullet 284 in 292 exh @ 0.50
lift 765 int 733 exh
114 lobe sep 110 int centerline
2 demon 750 carburators on hoogan sheet metal intake
plugged powervalves

thinking about 76 78 jettings in carburators
is this god to start with ?

thanks

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Re: start jetting 406cui 18 degree engine

Post by ProPower engines » Wed Oct 11, 2017 4:57 pm

most time you go up 10 jet sizes when you plug power valves to start then work up or down as needed.
What you are starting with is almost what they use out of the box with a power valve.

I would go up 10 sizes front and rear from the out of the box sizes if the power valves are blocked and go from there.
If you plan to dyno tune to get you close it will be easier then just trying to do it at the track.
Real Race Cars Don't Have Doors

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jmarkaudio
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Re: start jetting 406cui 18 degree engine

Post by jmarkaudio » Thu Oct 12, 2017 9:16 am

Depends on the rest of the calibration, emulsion, idle feed location, air bleeds. If they were not set up for a tunnel ram they need to be. Jetting will be in the 78-82 range dependent on the calibration. If you want to list bleed and emulsion info I can give you suggestions.
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hjallle123
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Re: start jetting 406cui 18 degree engine

Post by hjallle123 » Thu Oct 12, 2017 1:41 pm

carbs are set up for tunnelram intake

dont have number on airbleeds or emulsion

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