Discussion in 'Small Block Tech' started by Bradley Newsom, Aug 15, 2019.
My vacum secondaries will not open from a dead stop, to big of a cam not enough vacum ????
Vacuum secondaries should NOT open unless the engine requires the additional air flow. If they do, the engine will bog.
Have you tried changing the springs?
Not knowing ANYTHING about your combination makes it very difficult to advise you.
From the line it will not even spun the tires but has enough power to chirp the tires when it shifts to second
Oh it has 3.42 gear.
Look at your ignition timing. Get the mechanical advance in sooner.
What cam are you running? Torque converter?
There not suppose to open from a dead stop.
Do you have a TA intake or a stock intake.
Stock intake does not like square bore carbs if you use the adapter.
You would then have to run the Q-Jet with the stock intake that would be better.
If you run the TA intake then you can run any carb you like/want.
It has the ta intake
Do you have the stage 1 dual plane or the SP3?
Sounds like you need more tuning and more converter. Hard to say without any engine specs,cam specs what is happening,
You don’t even mention year of engine.
Vacuum Secondaries are supposed to open gradually, not from a dead stop like a mechanical secondary/double pumper style carb.
If you feel it "kick in" you are actually feeling the stumble recovery .
Edit : correct , smooth transition . To get rid of the stumble/kick you will need to change the secondary spring opening rate . Check quick fuel part number #63-11 .
You aren't supposed to "feel" anything or know the secondaries have kicked in. It's supposed to be a smooth transition.
It is the air gap sp3 intake. Engine is about a year old after complete machined. Comp cams thumper cam intake .050 235 exhaust 249.
That’s a pretty big cam. You’ll need a good converter and 3.42 gears.
You need more converter, get timing in sooner as Larry mentioned. That cam is abit lazy low end, and if your compression isn’t up over 9.5 there will be weak low end torque as well. The cam is more show then go, meaning its meant to make impressive exhaust sound . And it seems to like a lot of timing on the top end.
Much better cams available and you should check with your builder on what pistons went into the engine, specs , block and head milling to determine final compression ratio. Might be too low for that cam
Thanks, yeah it has no stall other then stock right now, going to try about 2800 stall, it seems that's when it wakes up
Don't buy an off the shelf converter. You will not be able to top these converters,