They'll bolt to the heads, no problem. Your pipes will be a little lower though because they're designed for a 351, which is about an inch higher, that in turn makes the collector an inch lower when installed on a 302. With a little "persuasion", you should be able to make them work.
They will not work I tried a set of mac shorties for a 351 on my 83 with a 302, after alot of time a swearing I finally got them on just for them to blow the gaskets, after further inspection I noticed the flang you hook the h pipe to was hitting the block and this prevented me from getting the the header tight on the head, thus blowing my new $20.00 superseal gaskets, not to mention getting the h pipe to fit after alot of prying and more swearing it leaked too. I lost $20 and 2 hours of my time I recommend getting the right header. I put all my stock stuff back until I could order the right stuff.