Issue with inline 250 at full throttle-Edelbrock 4 barrel

[da.slyboy]

Hi everyone, been on here awhile, just haven't posted much as most questions have been answered in the archives but am currently having and issue with my 250.

Recently rebuilt the head, and added a clifford intake with Edelbrock 1404 and Langstons headers, split out to dual exhaust. HEI unit

Currently it idles and revs nicely. Part throttle it drives and builds up speed as normal, but if I decided to stomp on it it seems to give me a little popping or lean sounding condition. I seem to lose power and have a hard time accelerating if I push too hard down on it.

Made a quick video to see if I was losing fuel pressure by stomping on it. If you forward to 2:45 mark it is the most audible of what is happening.

https://youtu.be/gN_HHNK2uyw

Just a note, ignore the flying vacuum hose at the beginning. I disconnected it because I though the can was providing too much advance (around 50 degrees WOT with connected. When the video was shot, I set the initial timing to 10 BTDC and had about a 30 degree total timing (again without any vacuum advance) I did plug the carb port.


I am stumped, at first I thought it was timing and tried multiple settings including driving it with just the mech advance and no vacuum. Then I thought it was a lean condition, but it seems my fuel is keeping up. Haven't checked to see if I have a jet clogged, but I'm mainly unsure if I should be chasing time or a fuel issue. Truck is a 4 speed (with granny) and the issue doesn't seem be a problem in the low gears. Only when in the higher more load bearing gears.

Any thoughts are appreciated.