409 Questions

Fathead Racing

Well Known Member
Supporting Member 7
Why is everyone pressuring me?! :D:D It’s true. My friends who own a body shop in town who did the paint on my coupe just bought an AF tester system I’m gonna weld in a bung and we will do some tuning once I get these bases replaced. Then I’ll just plug the bung afterwords. Don’t tell anyone though, can’t admit to o2 sensing on a traditional hot rod!! Ha ha
Dude, I'm on your side. I chose to spend a whole year tuning my carbs instead of just one day. AF tester, we don't needs no stinking AF tester.
 

409acoupe

Active Member
Really nice build. Love those air cleaners, match the valve covers:salute
Thanks man. yes the scoops took a while to source as i didn't want plain like most guys have. These are hand cast units by a guy in Australia. Lots of guys there and New Zealand that are big into the hobby and build some sweet stuff! I am going to fab oil bath style units for them at some point. Have one started. My Dad and i do a fair bit of metal fab work and have all the tools like english wheel, bead rollers etc to do that stuff. Again a guy in New Zealand that does metal spinning whose design i fell in love with gave me the inspiration. Was gonna buy a set from him but he isn't doing it anymore so gonna try my hand at making my own with a few twists. I don't like cookie cutter stuff if i can avoid it.
hutty.jpg
 

Clint

Well Known Member
The 55 jets are waaaay to lean. The stock jets are from .061 to.063. I ran .061 front to rear with no issues. My suggestion to you is front and rear carbs .060 and the center carb .061. The stock jetting was, with the turbo glide tranny, front .060, Center .060 and rear, .061. With the standard tranny, front, .060, Center .063 and rear .061.
I run 61 on all three of my carbs too and it is a 348. Runs great.
 

409acoupe

Active Member
Just received the new secondary bases from Vintage Speed. Man i have to say what a difference in quality between them and the speedway ones i have. Blades seal air tight and a much better machining job on the overall unit. the motor will be a lot happier once i get them swapped no question! So Just so we are all on the same page, we all agree i should bump the jets up to 0.060 for the secs and 0.061 for the primary. What would be the top range you boys would be safely happy with if i find she's still a little hungry? don't want to wash the cylinders down. Need this motor to last me the rest of my life, can't afford another 409!! :D
 

Clint

Well Known Member
Just received the new secondary bases from Vintage Speed. Man i have to say what a difference in quality between them and the speedway ones i have. Blades seal air tight and a much better machining job on the overall unit. the motor will be a lot happier once i get them swapped no question! So Just so we are all on the same page, we all agree i should bump the jets up to 0.060 for the secs and 0.061 for the primary. What would be the top range you boys would be safely happy with if i find she's still a little hungry? don't want to wash the cylinders down. Need this motor to last me the rest of my life, can't afford another 409!! :D
61 on all three carbs
 
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