Yup, I've had a pair of 315 casting heads with the later 3/8 intake bolts too.....and believe it or not, a pair of 920's with the 5/16 intake bolts! The combustion chambers are the same size, so, in that respect, there would be no problem running one with the other. It's just what did they do to make the later Edelbrock intake work. It's the intake bolt size and bolt angle that are different. The angle hitting the head and block are the same. Any time you use those 315 castings, (or other casting too) you should mag them for cracks. The 315's mainly had a crack problem on the outside flat surface between the spark plugs.