Chevrolet Repair: engine knock, hei distributor, engine knock

Question
I own a 1992 Caprice with a 305 that knocks when accelerating.  I replaced the knock sensor on the block, but there was no difference.  It only knocks when I am accelerating to get on the hwy to merge with traffic, otherwise ther is no problem.  The motor also runs very smooth under normal conditions.  I am considering putting in a earlier HEI distributor or I have a 1971 402 that is looking better every day.  Can you help with the Knocking problem?

Answer
Hi Reed, Check or replace the EGR valve. This valve is the part that stops engine ping. Also make sure that the timing is set correcty. The only other thing is carbon build up on the pistons, They sell a cleaner that you run through the intake to remove carbon.

                  Mark