302 heads-Is it worth putting them on a stock 318

Those 302's have their place and really should be used for specific purposes. Hardened seats are good. The small heart shaped combustion chamber is good for efficiency and to raise compression over a stock open chamber 273/318 head. Are they going to light the world on fire? no. Are they better than many stock 273/318 heads. Yes in some ways. I wouldn't use them on 340/360 blocks thinking the chamber shape and size are the magic. The small ports will spank you every time on the larger bore and cube engines. And like many here have mentioned, hogging them out to big cube size isn't a good idea. Might as well start out with a J or X head or carve on some aluminum's. Have a set of 302's available and you need a replacement (I said replacement and not necessarily a upgrade) head for your stock 273/318? Clean them up, surface them if needed. Do a quality valve grind. You can go one step further with a port match and a little bowl blend. No reason to do much more than that really. There's better heads out there to go to the next step.