When I start my car there a thinking noise and soon the car run for 5 min the ticking noise gone. But there a noise at 3000 to 4000 rpm a raddle thinking noise when shifting and driving when I lithely speed up and let of the gas. Noise from the motor. It hittle good. Oil pressure good. There lots of power. If I rev the motor the thinking noise goes with the rpm.

 

I know there was a tsb for a "head tick" on the 03 Cobra. Might be on the Mach 1 as well.

 

The Mach1 also has the tick if you go to the machiregistry there are a lot of post here is a link to the search I did today . 2003-04 Mach 1 Registry Owners Club - Search Results

 

its a rebuilt .core engine new in the crate from lkq performance from the state the heads maybe from a cobra.. whats a tsb..

 

TSB - Technical Service Bulletin

 

is it safe to drive it .. some day it sound like ticking time bomb about shout true the motor