If you want good bang for the buck cylinder heads and some more performance. I would agree a set of speed masters should work just fine on your 318. The compression will be what it will be(likely 8.0:1 or less) you won't be able to change that very much without milling your heads or going with different pistons. Stock 318s generally have pistons way in the hole. My stock 1977 318 had pistons that were 0.102 in the hole and with 63 cc heads that put my compression at 7.8:1
