Tried all day to figure it out. You can be rolling like 5 mph and snap it WOT and it bogs for a second, than springs to life and takes off like holy hell. If your rolling pulling about 2000 rpm you can snap it and no bog. Im 1 turn out on all four idle screws. Its a holley 750 DP, with serial 4779-9. Im running a Victor JR and trick flow 195cc heads, with 14 degrees intial timing. Im also running a 3000 rpm TCI stall and a turbo 350. IDle is set at 850 rpm with a steady 15" of vacuum.

Cam Specs.

TFS-K31401001 Fair idle, strong midrange power, 2,600-6,100 rpm powerband. 2,500-3,000 rpm stall converter. Compression ratio: 9.5:1 minimum.

228 intake/
234 exhaust .320"/.329" .480"/.494" 110

Fuels pressure it a speady 7 psi at idle and floats are set correctly. Thanks for all the help guys. this bog is driving me nuts.

 

What's the setup of your secondary pump?

 

If your asking about jet sizes i couldnt tell ya. I just opened the new carb and threw it on, set the floats and tuirned the screws 1 turn out. Im usually a EFI man, this is like my 3rd carb setup in a long time.

 

You need to tune your accelerator pumps. This is done by bolt/spring adjustment (the ones that actually push on each pump lever - should have been set properly at the factory, but you should check), shooter size & type (the nozzles out of which the accelerator shot goes), and pump size (should be okay with the stock 30cc, but sometimes you need the 50cc, especially on the secondary side).

First, make sure they're both squirting as they should. It should be immediate as the throttle is opened (won't happen on the secondaries until the primaries are about 1/2 open when the secondaries start to open). Squirter size is a trade-off between a lot of fuel early and fuel delivery duration with accelerator movement - the squirt volume is fixed by the pump volume, so you only get that amount as the throttle is opened. With a large squirter size, the pump discharges quicker so you get more fuel as the accelerator is first opened. With a smaller squirter, the extra fuel is delivered longer as the accelerator is first opened.

The pumps also have removable cams that can be changed to alter the way the acclerator shot is delivered.

Do some searching on this forum and you'll see more details on how to tune acclerator pumps.

 

Hmm thats what i thought but i mean damn its already shooting a massive load of fuel in on the secondaries side. and the backfire through the carb make sme think its lean. Do i need a bigger shot? BTW im also running a stock HEI ignition too much cash went into the head cam combo

 

is there a chance, the problem is too much pumpshot?,
What happens if... you 'half-stab' the throttle,
then full throttle two seconds later?

 

If you get stuck on this I have found it helpful to treat a double pumper as 2 separate carbs. I disconnect the linkage to the secondary throttles and tune just the primary side first.

If you disconnect the secondaries and the stumble goes away you know the problem is on the secondary side. If the stumble persists the problem is on the primary side.