The hydraulic lash adjusters are very oil sensitive. My 84 500 sec would hang an adjuster and make noise if I ran 15w40 oil in it. Put in mobil 10w30 and it would quiet right down.

What oil you running?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.