I was staring at my 6 intake/ exhaust manifold preparing to seperate the two and I noticed the numbers cast into the side 813. Noticed this because someone else on here showed their manifold and it had a different set of numbers. My set came off of a 67 292 and has a two stud exhaust port...thought that was odd because I've been reading that it should have 3 studs down there. And last but not least, will I have to modify the fuel lines out of the fuel pump when I switch to HEI? They look really close to the stock distributor and the HEI one has a very large head.