Just now pulled the head , it has a baffle on the piston and the head has a small but deep hemi chamber.
Hi Gordon
That one will make a very good stunt engine, we ran those many years ago, they run just like a ST 60 or ST 46, I used a Bolly 12 x 6 3 blade or a 12.5 x 5.5 2 blade, a Rev up 12 x 6 also worked well on that engine.
That version of the Como had mild timing like the ST 46 , and produced good power, I perfer it to the NEW G 51 we have now. Several people...me included put ST 60 piston and sleeves in the Como 51, that worked out well too

Regards
Randy