camaro engine

recently bought 80 camaro with home built 350. 410 horses at flywheel. Clicking noise coming from rear of engine. can hear it inside car as well. cam has lope to it but this almost sounds electrical it is consant and about 1-2 seconds apart. maybe exhaust not sure.

Maybe an exhaust leak, maybe a sticky lifter. WTH ws done to this 350 to get 410HP out of it?

I was told 410 at the flywheel, but that what I was told. I got a few specs (im not really sure about there being that much power) I was told it had 1.5 rocker arm ratio which alone makes me doubt 410. It definitly has a lope in the cam but i wonder if it has a large lift because 1.6 or even 1.7 would add ponies. I know it 60 over, high compression (not sure what yet), I'd imagine 202/196 76 cc heads high rise intake, rochester carb, i am new to the carb world (always tbi on my truck or Ls1) i do know it needs jetting down. Right now I just want to get it on the road (trans [saginaw] has 3rd and 4th shift postion reversed and shifter is a pain to find gears) 410 is not impossible at all from a 350 but with what I know Im thinking more like 340-385 Id buy it if it had a 400 crank.