273, or 318?

If I went with the 318, I was planning on getting a block, preferably an early one. Do you think the bigger bore would counter act the smaller ports? I plan on cleaning them up a bit.

it is all original numbers matching. The heads were off and had guides put in. Still had 1966 bearings in it!
Except for the pistons, the cost to go through a 318 will be about the same. Heads between a 273 and a Teen are not an issue.