no low end?

[2000.malibu.ls]

Ok now that im getting more accustomed to the car, Im starting to scope out in my mind whats going on. Im noticing in first gear it is very slow, and it craws to 35, its like the four barrel wont open, but when it hits second next thing i know im doing 75? Im also leaving quite a trail of white smoke behind me. Any clue what might be going on? Ive got a minor exhaust leak, and a minor oil leak, and a lot of blow-by.

Ive got a sbc 350, with a early model th-350 turbo, and a 373 limited slip 7 5/8 ss/442 rear end. Any clue whats up?

 

[custom442]

hmm, something isn't right. Mine moves like crazy in first gear with stock highway rear gears, but second is faster like you said, I think we can attribute that to the th350. What carb do you have? Mechanical or vacuum secondaries?

 

[monte olrac]

what kind of carb are you running? you cam/torque converter...do you have horrible rear end gears i.e. 2.73?

 

[2000.malibu.ls]

hmm, something isn't right. Mine moves like crazy in first gear with stock highway rear gears, but second is faster like you said, I think we can attribute that to the th350. What carb do you have? Mechanical or vacuum secondaries?

um, idk, its a edelbrach 750 performer, mechanical choke, I know it has a vacuum line hooked to it,so that makes it a vacuum secondary right?

 

[monte olrac]

sounds like too much carb, since its an edlebrock try leaninng it out some

 

[SScamino]

a 600 is plenty of carb for a 350, unless you plan on draging the car, the 750 would be better on the top end, not the low end

 

[2000.malibu.ls]

a 600 is plenty of carb for a 350, unless you plan on draging the car, the 750 would be better on the top end, not the low end

that would explain it then! thanks! so a proper cam/intake setup would liven up first gear then?

 

[custom442]

Well it's not necessarily too much carb, it sounds like your secondaries are slow to open, which means it could be a tune problem.

Does this happen: when in first gear, you smash the pedal to the floor and it lags then starts to pick up slowly?

 

[2000.malibu.ls]

Well it's not necessarily too much carb, it sounds like your secondaries are slow to open, which means it could be a tune problem.

Does this happen: when in first gear, you smash the pedal to the floor and it lags then starts to pick up slowly?

yes? tuning problem?

 

[custom442]

Well it's not necessarily too much carb, it sounds like your secondaries are slow to open, which means it could be a tune problem.

Does this happen: when in first gear, you smash the pedal to the floor and it lags then starts to pick up slowly?

yes? tuning problem?

First tune the carb so it's idling nicely, has the ideal idle mixture (which you can test with a vacuum gauge, google for more info), and set your floats at the optimum level if needed.

Make sure you have a good vacuum connected to your secondaries, and it sounds like you need to tune the secondaries to open sooner. This you have to tune by driving and testing (it’s recommended to test in high gear), because they are supposed to only open under a load when you mash the pedal to the floor. Vacuum secondaries open at different rates with different diaphragm springs inside. Lighter springs = open sooner, stiffer springs = open later. What you’re lookin for is a spring that makes your secondaries open a tad late after you step on it and ease into the extra power. You shouldn’t feel a jump with vacuum sec. Google around to find some instructions or kits with different sized springs. It wouldn’t hurt to call edelbrock and get their advice also.

There are also tricks you can do to find out if your secondaries are opening, google and see if you can find some

It also sounds like your power valve could be opening too late. You’ll need a vacuum gauge to test this and buy the correct valve.

Here’s a test you can try to make sure your power valve is working – turn the idle mixture screws in all the way at idle and if it sputters and dies then the power valve is working.

I agree 750 cfm is kinda big, but it can fit just about any engine if tuned properly. You might also look into jet sizing. But you don’t need a new carb, just spend some time and work tuning, go check out a book on tuning carbs at the library.