there are no more syclone/typhoon engines. You will gete a L35 normally aspirated 4.3 replacement. Even if a dealer claims they can get it, 1) they are either lying, 2) dont have a clue, or 3)have had one sitting around for the last 5 years and nobody picked it up.
LIke motomouth said, there are plenty of threads on this issue. Best bet is to do a stronger aftermarket rebuild, or find someone who has a spare motor. let me know if you need assistance with a rebuild.