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Author Topic:   carbs
posted July 01, 2004 08:56 PM
No not the eating kind... If a carb is jetted correctly for a 350, am I correct in thinking it should be fine on a 406? I've always thought of it was a air/fuel metering devise. Any other thoughts on this? THX and have a great 4th to all!

posted July 01, 2004 09:15 PM
I would think if your using the same heads and intake you should be real close.

rico 08
posted July 02, 2004 08:15 AM
Maybe,you know a funny thing i've noticed over the years is that sometimes a 350 will require more jet than a 400.My thinking is the 400 with a longer stroke actually pulls more fuel thru the boosters where a 350 you need to use a bigger jet to make up the difference.Crazy i know but i've seen it.

posted July 02, 2004 08:22 AM
rico hit it.

Different combos have different vacuum signals and that is what the carb sees. An engine that produces more vacuum will pull more fuel through the same size jet than a motor with less vacuum.

posted July 02, 2004 08:49 AM
My carb guy, which is very good, also told me that more compression will require more fuel. I switched from a 350 to 383 and the jetting is almost perfect.


posted July 02, 2004 07:29 PM
KP can correct me but I'd say dirtbuster is right on. Vaccuum is the ticket If it has the same Idle vaccuum reading as the other engine and the same max vaccuum reading then I would say that you'll be close. Less idle signal will require more jet.

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