Originally Posted by
Revo-lution
What's the difference in these two Nova engines? Is one a Turbo? Both are 21-5k with purple heads (not blue or black as in rex or top). One has a flat piston and one has an indented piston.
The flat piston is the older version, while the dished/domed piston is the newer version (as far as I know). Nova typically reserves dished pistons for their higher-end engines, since they require more machining and steps to produce. In theory the dished piston engine is their best version.