273 swap to 318/ build, cost, potential, daily driver

The Magnum engines are better tech, are low cost and easy to obtain. The 360 is preferred because its bigger. The bores of either 318 or 360 Magnum most of the time are very healthy due to coming from a fuel injected engine- no flooding and washing down of cylinders like an LA engine with a stuck float in the carburetor. The Magnum heads have a nice efficient small comb chamber. Unlike an LA Head but stock Mag heads are limited to .550" lift stock. (Valve guides will need machined down for more lift. The Magnum engine is a Hyd Roller cam engine. Go with the stock cam and enjoy idle to say 5200 RPM performance or send the cam out for a regrind and make more power. Those HYD roller cams produce amazing power WITHOUT a ton of duration. Magnum heads will be cacked between the int and exh seat but they're all that way and apparently it poses zero problems for a stock or higher perf build. On FBMP a complete 360 will typically be $300- $600- at least in my area.