318-3 Closed Chamber Truck Heads
Yes, the Fire Arrow had a 2.6L NA motor. It was pretty potent in that very light car.
The best 2.6L's are from the later Mitsubishi Starions and Chrysler Conquests. When the turbo's were added in those cars, the factory added piston coolers (oil squirters under the pistons from the main gallery) and a better oil pump system. I think the rods and crank were better too. Stock pan on the turnbo ones even had some basic oil baffling. You can eliminate the balance shafts with a kit. Up the SCR to a true 8.2 with VW forged flattop pistons and the torque gets good off-idle and covers most of the turbo lag if you have the right turbo. I ended up at 1.75 HP per ci, totally reliable under racing conditions, with 14-15 psi boost limited with a wasategate in rally use.
Note that the earlier 2.6L's did not have as good of an oiling system or crank. So they are not as durable if you push on them hard as the later turbo'd versions.
The 1.6L's were good too. Nice little hemi heads that could be ported out to well over 200 cfm flow with bigger valves.