Engine noise

Need some help. I have a 69 Camaro with a 454/450hp motor-motor is new with only 450 miles. The car sat for about a year with monthly start ups at a dealership. I brought the car home on a flat bed and drove it for the first time today and it seemed to start and drive fine and after about 3 miles i got a loud ticking from the passenger side valve cover area then it stopped after a mile or so and when I almost got home it started again until I shut it off. I waited a few hours and started it again and the loud ticking was there and stopped after 1 minute. Any ideas on whats going on before I take it to a mechanic.

Thanks,

Mike

might be a sticking lifter.
Try draining a qt of oil and adding a qt of Auto trans fluid, type F. run the engine for 15 minutes or so and then change the oil and filter. The type F fluid is high detergent and will remove any varnish deposites that may be gumming up the lifter. After that it would be down to pulling the valve cover on that side and checking the valve lash. If you have rocker clips (they prevent oil from going everywhere ) put them on and start the car with the valve cover off and see if you can isolate which rocker/lifter is ticking.