Originally Posted by michael 1
any of the 321 will do
The jp fx R-03 engine is based on a novarossi rx321p only difrence from the later novarossi 321p engines is rear bearing size the jp fx R-03 has a 25.4x14x6 mm bearing and the later nova 321p engines used a 25.8x14x6mm rear main bearing. Outher than that there almost identical. I am not shore if the very latest jp fx R-03 engine uses the latest size bearing 25.8x14x6mm. If some one has a recsent production date jp r03 Please let me know. Regards Jeremy.