If you are talking about the 1976 and 1977 Cross Country 340 and the 1979 El-Tigre Cross Country 340, yes they are rare. The 1976 and 1977 versions were based on the 1976 Pantera chassis. The '76 used a special built 340 Free Air Suzuki based on the 5000 series 500 FA in the Pantera. This engine was putting out somewhere in the mid 50's for hp. Not bad for a 340. The 1977 version made some chassis tweaks so they could install a tamed version of the 1977 Z oval racers 340 Liquid engine. This engine was tuned for durability and some rule requirements verses top end power like the oval racer version. That was the end of the Pantera aluminum chassis based sleds. For 1978 they made a 340 cross country kit for the consumer El-Tigre and finding a kitted sled is very hard. For 1979 they made two special El-Tigre's in both 340 and 440 LC Spirit engines with a special rear suspension and a special track. The 440 cross country is easier to find today. The much rarer 340 version is not. Demand was high enough from racers that they sold 340 top end kits to make a 440 a 340. If I had to guess, I'd say no more than 500 340 XC El-Tigre's made, and about 1000 of the 440s built? They also made a cross country kit for the 1975 El-Tigre Z that included parts to swap in the trail skid frame to replace the nice but fragile oval track skid. New seat and a twin tank kit too. They made twin tanks standard on the 1976 and 1977 models and I think they were an option on the 1979's. However, don't get fooled by the standard 500 FA Pantera chassis as this used the same twin tank set-up for the lux touring sled from 1976 to 1978. It was real easy to install the back tank in many cat models from those years.
The one thing that I'd add to GB's reply is that the '76 was built in 2 versions, a consumer version of approx 500 built, and a race version of approx 125 built - the race-built version considerably tougher to find than the consumer build - additionally, the '76 340 F/A engine is tough to find, as they were not real durable.
I'm new to the forum and sort of new to Vintage Arctic Cat sleds. I recently picked up a 1976 Cross Country Cat. It's mostly complete but in very rough shape. I have begun collecting parts for a complete restoration. The motor has Compression and Spark but I have not started it yet as i would like to inspect the bottom end closer before I attempt to start.
My CCC has a single pipe but there is evidence it had twin pipes at one time.
I am very familiar with most all the parts that are and aren't available for this sled and which parts from the Pantera that will cross over.
Can anyone tell me if there are pistons available for this motor.