Difference in 273

Dartswinger70 said
Makes me wonder what similar internals would do in a 318.

If you are meaning going with decently high compression pistons than the stock 318 low compression pistons, then it would become a 273 on steroids.

It will be a lot more like a 340 than a 273 if the larger LA or Magnum heads and breathing parts are installed.

There are newer and a bigger variety of cams and such for these LA engines now, so it does not make so much sense to me to use the older cams.