Recently, We replaced the Bing Carby w/ a Rotec's 40 TBI to my Jabiru 3300.  Here the results: (After 25 hours running)  Still using same throttle system and air box system.   

1. Now can reach 2850 rpm in static run-up.

2. Shorter lift off distance.

3. Fuel burn @ cruise 5gph.

4. EGTs closer.  CHTs cooler.

5. Able to control mixture.

6. Very easy Starts.

7. Only use electric fuel pump for first start of day w/ primer once.

8. Climb 1200 fpm @ 90 mph.

9. Cruise 4500 ft @ 115 mph @ 2650 rpm. 

10. Oil temps normal in cruise.

*We added the new hallow lifter & rocker system. too.  Did away with tubes between heads.  This has assisted in cooler heads but the oil temp are higher in climb out.  We think this is because the oil pulls more heat off the heads and returns it to the crankcase.  However, the higher temps are still in climb range as posted by Jabiru.  Note, My 601XL-B was topped @ 700 hours.  Stuck rings were primary issue.  I blame the Bing.

Other Mods:

A. Moved gullwings from top of heads to the bottom.

B. Added 2 inch lip to bottom of cowl outlet.

To do list:

A. Enlarge outlet at bottom of cowl.  Outlet should be 3 times the size as the inlets.

B. Enlarge oil sump to at least 4qts. 3 plus quarts of oil is not enough for a six cylinder.

C. Chg prop for cruise (longer prop, same pitch).

I wish to thank my Brother Bo and his son David.