434 Help
I took my brand new 434 sbf to the track this weekend. The motor ran great on the dyno, it runs great and clean in the burnout box but it seems to struggle to pull past 5000 RPM, it eventually will but is not reving clean after that either. I pulled plugs and they looked pretty lean so I fattened it up a total of 6 steps and it didnt change it, I finally tried a new carb and that didnt change it either. I am thinking it is fuel pump now but wanted some other opinions. What do you think?