The former Esci M60A3TTS kit has been reissued by Revell of Germany as kit #03057 and not by Italeri. Italeri reissued the ex-Esci M60A1 Blazer and M60A1 as kit numbers 6391 and 6397 respectively.
Unfortunately, neither the Italeri M60A1 Blazer or M60A1 reissues will build into an M60A3 out of box. Regardless, the Revell M60A3 is the best M60A3 available.
The Tamiya M60A3 kit (#35140) is pretty decent and if you are not a rivet counter builds into a fine late 80s M60A3TTS. Unfortunately, it is current out of production.
Another option is the Tamiya Desert Storm USMC M60A1 w/ERA (#35157). It contains all the necessary M60A3 parts from the M60A3 kit with better road wheels added in. It replaced the finned aluminum wheels with smooth steel wheels. Most M60A3TTS tanks had a mixture of smooth and finned road wheels. No US Army decals though.
If you look around eBay or at swap meets, you can still find the old Esci kits here and there. The original kit numbers are:
5039 M60A1 Patton
5040 M60A3TTS (Tank Thermal Sight)
5042 M60A1 Blazer (IDF not USMC up armored variant)
Eduard made a PE set for the Tamiya M60A3 (could be used with the USMC M60A1). It was set #35073. Although OOP, you should be able to find a set somewhere.
Barrel Depot does an aluminum barrel with thermal shroud. It is #35004. The thermal shroud was unique to the M60A3TTS.
One of the poor spots on the Tamiya M60A1/A3 kits are the tracks. AFV Club makes an excellent set of replacement tracks for this. It is set #AF3510 and runs about $10-15.