What are yor plans with the car besides street/crusing? Do you want to do 12s in the 1/4 mile? Is the car original? Do you want to keep it that way. There's nothing wrong with a 273 for cruising. Heck, you could even go 10s with it - given enough work.
A lot of guys with desirable cars that plan on keeping them tend to pull the original engine and stash it in a corner and then build themselves a solid 340 or 360 to "cruise" with. Or you could drop a crate in it.
