1987 Looper v4 140 RPM only 4000

[nymack66]

Guys , Any idea why I can only get 4000 RPM at WOT ? Compression is 130/120 across all ports,
What size Jets do I need to install on my Carbs ? Currently 58D installed.
New everything on the engine,coils,plugs,wires,harness you name it minus pistion and rings !! . See photo at www.nymack66.com , I am restoring this baby..If I can get an album here it will be great I will move my pictures up