well recently got the stang somewhat drivable. replaced all of the brake lines/fuel tank and lines, alot of electrical work, replaced the clutch that was seized. car sat for 17 years in a field. this is a 289 with the 1717 Shelby gt350? 4bbl carb on it... who knows how it got there... with T-10 anyway i drove the car for the first time on some back roads. il have to say its kinda scary! brakes are a lil iffy, suspension is as loose as.. well.. speedo don't work along with most other electric things, well my main question is how the hell do i tell if the secondaries are opening on the carb? ive never driven a carbed car before.. so im clueless.. i can say that this car has a TON of power. i was experiencing a high idle issue while i was driving it.. idling at like 3k.. it just happened all the sudden.... so i was doing 30mph in 3rd gear and i blipped the gar hard/fast to try and lower the engine rpm and it barked the tires!.. in first it will light the tires even cursing at 20mph. this thing somehow has a set of *****... i drive an srt-8 300 so i know what power is. this things got it... but anyway when i got it back home i removed the breather lid to inspect the carb.. thinking that some butterflies were stuck open.. nope.. and i saw loose rust prolly from the hood.. laying inside the secondary barrels.... now if they opened that rust would not be there... right? but how so much power if im only running on the prims?????? how do i tell if the 2nds are opening?? i freed up the levers and all.. i can open them manually.. but maybe a bad vacuum diaphragm? thanks all!

 

you remove the hood and sit on the cowl while a buddy drive you down the road with the air cleaner removed lol j/p dont do that....if you idle is hanging you probably just need a new carb spring to pull it back closed...either that or you have a vacuum leak....

 

Vacuum secondaries are load based and you need to get into the throttle to open the secondaries. With your description of the car it sounds like it is possible that you didnt get into it enough to open the secondaries cause it wouldnt be safe. Its also very possible that the carb needs rebuilt, bad diaphram, plugged passage, saft corroded in place. etc... I know thats not much of an answer but until the car is safe to drive hard its hard to tell if the secondaries work.

Also if the breather was on it shouldnt have rust making it to the carb, check out the inside of the breather and if there is rust there dont use the breather till all rust is removed.

Is the carb an autolite or a holley/edlebrock/carter etc... What does the tag on the side of the carb say for numbers? What is the 5th digit of the VIN. The Shelby's used the same carb as the HiPo 289. If you are a K code car that would explain why the car has more go than you were expecting.

 

well the car isnt a gt. the engine is a 1967 even tho the car is a 65. but it has the small crank dampner that would suggest its not a k. but the numbers on the carb are 1717, its a holley 4bbl... what rpm would they open? or is it vacume/load?

 

What is the complete numbers on the carb. Its not a shelby carb, the GT-350s used the 4100 autolite. Holley 1717 is a casting number for the carb. Take a look around the carb with a mirror and flashlight and look for any more numbers and i will be able to tell you what the secondaies should do. If vacuum then there is no set point for them to open, if mechanical then it is dependent on how the linkage is set(should be about 50-75% throttle).

 

No, they didn't, except for some of the Hertz Rent-A-Cars. The 65-68 GT350 used a center-float Holley LeMans carb. Oh, some early 68's were delivered with the Autolite 4300 until the Holley was approved.

Here's a trick for this on Holleys: The secondaries are vacuum operated. The diaphragm draws the control rod up into the housing. Place a paperclip on the rod, touching the bottom of the housing. Drive the car. Check to see if operation of the rod has pushed the paperclip down the rod.

 

hmmm... there is a small rod kind of hidden under the black plastic round thingy on the top right rear of the carb (closest to RR wheel) are you talking about the rod that pushes into the vacuum chamber il call it.. (black round thingy) if so i don't know if i could get to that rod with a paperclip... maybe a roach clip or would that squeeze to hard?.. yeah def vacuum.. i opened the primarys up all the way by hand and no movement from secondaries. if i operate the 2nds by hand (can only be done while prims are fully opened) i can hear a crinkling sound coming from the vacuum chamber.. whats in there? is it like the accelerator pump diaphragm? i replaced that because it was hard and non-functioning... if the 2 are similar can i just replace a rubber thingy like i did with the accel pump? i should of just opened it today... only 3 screws.. just didn't want to screw it up... i drove the car somewhat hard today... at a price. i got out on the road and nailed it in 1st gear... rally pak not hooked up and speedo don't work after clutch replacement... but if i were to guess.. at about 2500rpms the tires broke loose for a few feet.. i took it up to 4000 to maybe 5000rpms and shifted to 2nd, broke 2nd loose pretty good.. but at no point did the 2ndaries open.. at least the plates were still covered with loose dirt. but it never all of the sudden sounded different or gained random power.. so then i turned into the neighboring subdivision and i guess i turned to hard.... the battery flew into the alternator.. got chopped up and exploded. engine died. (can't run without the batt??) scared the crap outa me. so now EVERYTHING is covered in battery acid... all of the paint is faded and bubbled.. all of the wires, plug wires everything are melted/torn... rad hoses now need replacing.... what a mess!!! we used a giant box of baking soda and a pressure washer.. stained the driveway killed the grass... sucks! oh and i read on another forum browsing Google that the 1717 4bbl holley was from shelby gt350.. maybe not?