Aw, a 273 thread. I love those. Nothing wrong with a 273. Good little engines. My buddy who has been a stock racer for years ran 273s back in the 60s in Junior Stock.

There’s a lot of things you can do to a 273. The stock flat top piston with a 920 casting head garnered a respectable 8.8 to 1 CR, factory rated. With a little massaging its easy to get the motor over 9 to 1. Lots of things can be done to lighten the internals to bring up the revs.

As far as valves, the problem with larger valves is shrouding. You can get around that by cutting down a 1.88 valve to 1.82 on a .030 over bore block without the shrouding problem.

As far as heads the 920 is the best flowing head. With the 1.92 valves, stainless of course, some bowl blending and pocket relief the 920 will give the 273 more than enough airflow. Of course there’s the swirl port heads which seem to favor the 273.

As said, th 273 depends on low end torque which means steep gears. On my 273s I found 3.55s to be the gear to run on the street.

Nothing like a 2800 pound Valient with a 273 running a 4 speed and 3.55s.

273s running stock eliminator and super stock hold their own. Ask Paul Wong out of Division 7 and Matt Steen running a 273 in Super Stock that runs in the mid 10s.