318 with random parts.
The early closed chamber 273 heads, when worked by someone that knows their *** from their elbow, can flow well when you use a better and larger valves and work on the intake shrouding a lot. Chamber shrouding is the biggest issue even with the X heads. The later open 273 heads helped in the shrouding issues somewhat.
Put a set of worked closed chambers on a 360 and with a 340 resto cam made more BUTT Dyno power from 1,500 to 3,500 RPM. It was not a 6,500 RPM drag race engine. It spent its life in the 1,000 to 4,500 RPM range with a few blasts above that.
The early closed chamber 273 heads, when worked by someone that knows their *** from their elbow, can flow well when you use a better and larger valves and work on the intake shrouding a lot. Chamber shrouding is the biggest issue even with the X heads. The later open 273 heads helped in the shrouding issues somewhat.
Put a set of worked closed chambers on a 360 and with a 340 resto cam made more BUTT Dyno power from 1,500 to 3,500 RPM. It was not a 6,500 RPM drag race engine. It spent its life in the 1,000 to 4,500 RPM range with a few blasts above that.