73 Mach 1: New Fuel System with Firing/Idling Issues

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Aus73Mach1

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QLD Australia
My Car
1973 Mach 1 Sports Roof.
Q code. 351-4V
C6 Auto, 3.25 Rear Axle, AC, Power steering.
Just a thought but that gasket on the top side looks like it is not compressed and could be causing an air leak under the carby and causing some of the issues you have.

David

 

Hemikiller

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71 Mach 1
65 coupe
Just a thought but that gasket on the top side looks like it is not compressed and could be causing an air leak under the carby and causing some of the issues you have.

David
That's what I thought when I saw the gasket. 

OP, be sure to get a gasket that seals well, as some of the generic Holley types won't seal the perimeter of the base plate casting. The 4300 has vacuum passages cast into the base plate, which will cause a high idle situation if they are drawing outside air. You'll also want to check the base plate with a straightedge to ensure it is flat and not bent/warped from over tightening. 

 

Millertime

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'73 mustang fastback mach 1
I’ve run out of time working on the engine for now, I work 3 and 3 rotations as a geologist in northern Canada so I’m thinking it might be best to invest in a new manifold/carb that hasn’t been fiddled with as much by the previous owner. I’ll check out that carb Don linked and if there’s anything else you guys think I should replace, feel free to let me know! Really appreciate all of the help 

 

Aus73Mach1

Well-known member
Joined
Aug 5, 2019
Messages
126
Reaction score
79
Location
QLD Australia
My Car
1973 Mach 1 Sports Roof.
Q code. 351-4V
C6 Auto, 3.25 Rear Axle, AC, Power steering.
I used a Holley Brawler Carby. No adjustment was needed for idle, choke, etc. Also has sight glasses for float levels. Works extremely well on the 4V through full throttle range.

 
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