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Holley 770 on a 496 - Change Jets?

1151 Views 1 Reply 2 Participants Last post by  BACK FROM THE DEAD

My 496 build is moving along, and the plan is just to use the Holley 770 Street Avenger I have on my 396. 100% street motor.

The plan is to use the 770 on the initial fire-up, and run it to see how it goes from there. The carb has been trouble free since day 1 and has not had any changes made to it except the spring for the vacuum secondaries.

Will this carb need to be re-jetted, or should this be a wait & see approach?
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Wait and see. Chances are that if it was jetted correctly for the 396 then it'll be about right on the 496 too.
There is a bunch of theory behind it, but basically from what I've hear and read on the subject since carburetors are just a basic metering tool once jetted properly for the air CFM they flow they'll run about the same on many different engines regardless of size.

I'm trying to remember where I saw it but there was a video the other day where a guy explained it in depth and it made a lot of sense.
But the basic idea was that once the carbs fuel jets are dialed properly in accordance with the air flow of the venturies it will meter fuel appropriately based on the vacuum signal the engine makes regardless of the engines size.

The guy was recalling times in the past where they'd pulled a 390 CFM 2-bbl off a Pinto and put it on a bigblock Ford 460 and it worked fine w/o re-jetting, and another time they pulled a larger (650-705 something) 4-bbl off a 360-390 and put it on the Pinto and again it worked fine.

I'm sure it's not completely universal and that it won't run at it's optimum performance level without fine tuning, but my point was that it'll be close enough.
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