I like the idea of a good 273. I'm going to be using a 273 crank and rods in my 340. But again it comes to value. Value meaning cost vs. reward. To get a 273 done well, will cost more money. Custom pistons, and custom head gaskets, plsu a couple extra blueprinting steps like centering the chambers over the bores and notching the bores themselves. I think the larger LA head ports will be a bit much for the 273, but an early A is light, and with the right gears I don;t feel most drivers would notice any loss of response. To each their own. I have choices for my '65 from a slant 225 up to a 360 and I'm still not sure which will get the knod...lol.