Holley sniper w/ headers troubleshoot
Hey all, have had a Holley sniper EFI system installed for about a year now on my 258 and it was running pretty good. My cast headers cracked and I replaced it with Hedman Headers (I do not suggest these headers, they do not clear the engine mounts). At the same time I upgraded to the 2bbl BBD cast intake as my motor came with the 1bbl. After some headaches, bashing, and grinding, I got both headers installed and now the engine is running like trash. I have reset the Holley Sniper to relearn the base fuel map etc etc and still need to drive it a bit to let that dialed in. It idles fine, actually better than it's ever idled, but my major complaint is that it runs the best on about 10-20% throttle, anything more and it stutters/spits or just falls on its face and doesn't have any power. If I hold it on 10-20% throttle it will accelerate way harder than WOT. I have tried to scope out a vacuum leak by spraying down suspect areas with starter fluid and haven't found anywhere it revs up due to pulling in air. Right now I am running the factory air cleaner (long snout style) but will be replacing it with a round type, replacing valve cover breathers and PCV's etc.
My leading suspects are exhaust/intake leaks, it's always an issue with what you just worked on right? But what are other ways to find either? I have a mechanical fan on the front and I am considering pulling the belt so I have still air to feel for puffs (running it for very short times).