New Exhaust=Stumble...
 

Running 358sbc pushing 360hp @5300. I run Stainless Marine manifolds with straight 4" thru-hull exhaust. I also run a Edelbrock (weber) 600. Well Im still dialing everything in. I have heard bad things about the slip-in silencers which I was using. I took them out and picked up almost 2mph (per GPS). Well I have ordered the Shotgun III's and am waiting for them to arrive. My question is this. After I took the silencers out I got the increase in speed but also got a pretty bad "bog" when I throttled down at about 3500 or so rpm's... The bog was just on the initial jump on the throttle then it came to life and ran fine. I really try to not holeshot it much from a standstill due to my Alpha. What should I look for first...I am leaning towards the accelerator pump shot for the bog and going up on the jets and or rods also. What does everyone suggest for getting the right mixture for WOT? Rod,jets or both..I have read to try going up in size on the jets till you loose rpm's then back off one is this correct. Also should I worry much about setting the primaries? How do you go about this....Sorry so many questions sometimes it's better to ask here than try to guess or go thru pages of tech mumbo jumbo .......
Thanks

"Bad-Habit"

You may be able to fix it with more accel pump shot. What has happened is that by removing exhaust restriction you speed up air flow through the engine and the carb jetting can't keep up. That is what the accel pump is for. If you increase duration and/or volume of accel pump shot you add more fuel and should not have the lean stumble you are getting.

you gained power becuse of the decrease in exh restriction just like he said,but with the cam it takes to make that 360 HP,sounds like you lost the back pressure it takes for the vacume secondaries to come in as fast as you need them to,just a recommendation....but a 750 double pumper with manuel secondaries(which has dual accellarator pumps)will make that thing run like a scallded dog....make sure you run a larger spark arrestor than stock to get the increased air flow into the motor....

jets - up a size.
then mess with rods.

Im running a 9x3 K-N. Cam is a roller. 218/224 lift with 503/510 lift with a 112 LSA

Bad-Habit

defietly more carb....about a 400 dollar investment....spark arrestor should be fine.......night and day difference....I put these carbs on all my 350s that we build here above 300 horse....