i just purchased a 1990 iroc with a 5.7 L98 there is a bad rattle in the lower end at start up and a big puff of smoke follows it has 111000 miles on it also the oil presure seems a bit low any help or should i look for a crate motor if so what kind will bolt right up without any computer mods

thanks
russ

also if you know someone in tampa fl who can do the work let me know

 

What color is the puff of smoke? Black is fuel... white is coolant... blue is oil. This is very important.

What is your oil pressure? A stock pump will be around 5 to 10PSI at idle, when cold.

 

THE SMOKE IS BLUE, BUT THE RATTLE IS WHAT IS CONCERNING ME

 

He's asking cause the smoke and rattle could be related. Blue smoke and rattle at idle at startup to me sounds like your getting oil into the combustion chambers 'causing detonation and the blue smoke. Basically something's worn, rings, guides, seals, something, so when the engines cold it lets oil into the chamber, then when it heats up and everthing expands at different rates it closes up the clearances a bit and fixes the problem a bit. If it's really way down in your lower end, it's probably worn bearings. Either way, hate to tell you but, it looks like it's time for a rebuild or new motor buddy.
John