As has been mentioned so far.......what is the purpose of this car? Cruiser? Drag racer? Pro Street? What rear axle gear are you running? If you still have the stock 7 1/4 rear, it's not suitable for ANY increase in horsepower. The stock 9" brakes aren't either. Which transmission, as there may be some upgrades needed there too? If this is just a stock setup for cruising with maybe a slight increase in horsepower, there's nothing wrong with building your 273. Just keep in mind that pistons are fairly expensive and you're already giving up some horsepower vs. a similarly equipped 318/340/360. With all due respect to Professor Fate, the LA 318 started in 1967, just not in an A-body. The first 318/4 was in 1978. The '66-7 273 intake will be a bolt-on for the earlier 920 (66-7 273 and LA318) and 675 heads ('68-72 318). Same intake and exhaust port sizes with no LH exhaust manifold issues. If you're going to use the 920 casting heads, those are closed chamber and work great with a 273 with whatever pistons you chose. If you use the 675 heads, you may want to see if higher compression pistons are available (Eggy?) or you may want to do some head/block milling for a higher compression ratio....whatever you're trying to achieve. If this is going to be a drag car, or, pro street a bigger cube starting block would be a better choice, and the sky's the limit on what you should get taking your budget into consideration.
