Which years were the "supposed" bad years of the LQ4 and LQ9 motors?

 

all I know is the 99 & 00 will not bolt up to the 4l60e and have iron heads.

 

AH maybe that was it, lol. I'm used to f-bodys but have reading up here and there but it was a long time ago aswell,lol. I'm trying to do a v6 to v8 swap(6.0) and i thought i read somewhere that there were some years where the 6.0 wasn't as strong or something

 

bascially just the 99-00 ones with the crappy iron heads

 

ok thanks. I seen low prices on '00 and was wondering