96 Cobra motor rebuilt sound

hey guys, was wondering if anyone has encountered this issue or could help me out with..basically, got my 4v motor rebuilt i.e. everything new except for crank and cams....heads were rebuilt and ported and engine was bored to 0.20 over with new rods and pistons and all new timing accessories. Engine is in car and hasnt ran for even 50 miles...PROBLEM i am having is a rattling noise that appears to be coming from intake manifold...I have no clue what this sound is and i dont know if it relates to the actual rebuilt engine itself but i dont want to harm it by driving it...ANY ideas on what the problem could be.. I cant imagine it being hte engine as it was professionaly rebuilt etc..
I dunno..

Please respond with any advise

hey, i talked to mechanic and engine guy and they definately said it sounds like a lifter and that its not getting any oil up there... it has a new oil pump....
it is more annoying than anything but i dont want to drive it if its gonna cause serious long term problems...hopefully ur car isnt effed up from the bad lifter, did u used to drive it with your lifter noise?

also, the lifters are original with 75k on them. i would hate to have to replace them especially since i just paid a boatload of money to pull engine and have engine rebuilt etc...
thanks for your help