High RPM flutter and pop in Div 3 pulling truck
 

Need some advice guys, Have a 468 big block with oval port big valve heads,10.5 comp ratio, Team G intake, modified 850 dbl pumper w/50cc pumps on both ends, and correct squirters and screws, #86 jets in primaries and #90 in secondary, Lunati solid lifter cam, gear drive, K-motion K1000 valve springs, checked and pressure is good. Brand new MSD ign. 6AL box, Pro Billet Dist, Blaster 2 coil, Taylor 409 10.4 wires. Holley Blue pump w/ reg, all #8 stainless lines, Running 7psi fuel press. Running VP110 fuel,We have been fighting a flutter and pop starting around 3000 RPM and never coming out of it it will go ahead and turn 8500 but it is fluttering all the way through the range, We have changed all the ignition parts and have not made any difference. It seems to be heat related cold starts it doesnt do it as bad. Was told have a lean condition need to increase jet sizes by 2-4 sizes. Plugs look fairly good a little gray but not too bad, I am just lost guys, any help would be greatly appreciated, Thank you, Dennis

High
 

Maybe fuel pressure. Do you have a pressure gage where you can look at it while pulling a load wide open throttle?

Blue pump is not much flow. 110 GPH. Most good pumps are 350-450 GPH

Areomotive A2000 is a good one.

Guy from Monee Illinois has a new one for sale for $300 under Fuel Systems section of ads on this site.

Thank you for replying, No we cant see the pressure while pulling just have a small gauge under the hood. after it warms up a little you can get it to start fluttering while setting still, the pressure is not dropping while running the throttle under the hood. But it still has that fluttering around 3500 on up, I've got some bigger jets on the way and my friend has a magnafuel pump that we are going to try. Hopefully I can see something change, either get worse or get better, everything I have done has not changed anything even a little, So we'll give it a try and see what happens.. Thanks again, I really appreciate the advice!!