Ok,.. Here's my setup;

350 SBC with Vortec heads (NAL 19210007) camshaft is hydraulic flat tappet with .435 in. intake lift and .460 in exhaust lift with 212 degree open duration intake and 222 degree open duration exhaust lobes at .050 in. ground with a 112.5 lobe centerline. Holley 83670 670cfm Vacuum secondary carb with the stock 65/68 jets and 6.5hg power valve. Edelbrock Performer RPM intake manifold. MSD 8360 Distributor with 12^ initial timing + 21^ in at 3400 rpm. .44 Plug gap. 6-7 PSI fuel pressure and 12-13 in Vac at idle warmed up. TH400 with 2800 rpm stall and 3.80s out back. Vehicle weighs 2800lbs with full tank and me. I live in S. California about 1000' above sea level.


Ok,.. here's the issue;

Big bog on taking off. In drive or with no load the engine stumbles when the loud pedal is depressed. Past the bog the car runs fine and idles great. This is a brand new carb and I have tuned the four corner mixture screws for highest vacuum. Accelerator pump IS working at the crack of the throttle.


Ok,.. My thoughts;

Not getting the correct pump shot. I am posting pics of the pump discharge nozzle as I cant figure out the size. There are just two "lines" that look like machine marks on it and no other stamping. The pump cam is still is what came on the carb and in the factory position. I thought was odd for it to be in the #2 slot? I believe (both my wife and I cant really tell as it looks kinda brown) the cam is the orange one. I was thinking of increasing the size of the discharge nozzle a couple of sizes but cant tell what size I have now.

Ok,... What do you think / suggest? Thanks for your time.



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