If you going with the stock style www.turbobuicks.com have hardened ones for sale for a good price.
If you are going to use stud mount rockers the ones champion sale are scorpion & thats what I run.I herd bad things about them from people but I think they were talking about older versions...
well it all depends on what your looking for,you dont list the stall you are running but as long you match it to your stall its all in how hard you want to run it.
I looking into a 76BB to go with my 3400 stall I drive it on the street.:D
Yes it will cause knock if it get bad enough,It lowers the octain level in the gas when it mixes with oil.Did you use the stock style intake gasket when you reassembled? @ least i would put a 893 pcv in there they are the best for our cars.