57 carb issue

[RonnieK]

My 56 has a 57 312 engine with an autolite 4 barrel , runs great but the 4 barrel does not open when you kick it down. Is it a vacuum issue or a linkage issue? Ronnie K

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[Dale Leonard]

Post a couple of pictures of the carb. More than likely it is a linkage problem.

 

[64ZCODE]

Hey there RonnieK. My favorite subject. Here is an easy way to tell: Disconnect the throttle linkage from the carb linkage. Rotate the carb linkage all the way to fully open and make register marks (a sharpie will do fine) on the linkage and the side of the carb at the full open (WOT) point. Then reconnect the throttle linkage to the carb linkage and have someone push all the way down on the accelerator pedal and see if the register marks line up.

When I got my '64, someone had hooked up the throttle linkage to the wrong position on the accelerator linkage and as a result the secondaries weren't opening up. I had to get an adapter from Holley in order to connect the linkages at the correct point, but boy was it worth it.

Note you may need to adjust the throttle linkage to make sure you're getting full travel when you mash down on the pedal. For example, there will be a spec for your car for the distance between the pedal itself and the floor boards.

Doug

 

[JRP]

My 56 has a 57 312 engine with an autolite 4 barrel , runs great but the 4 barrel does not open when you kick it down. Is it a vacuum issue or a linkage issue? Ronnie K

Ronnie, I had a 57, 2-door hardtop with the same setup back in 1964. It was linkage not vacuum, at least that is what I had. Originally it had a 2 barrel, and when I put the first 4 barrel on it, as long as I kept my foot out of it, the mileage increased. Then later had a 56, 312 out of a rear-ended T-bird. Bored and stroked...it was great. Had two holly 4 barrels, cutouts and I never found out how fast it would go. I chickened out at 160. I guess there was a little self preservation in me, even at 17.