Can the 305 be used with LT4 heads & springs or do the springs req changing

 

Depends on 3 things:
1) what rockers your using. cc305 w/1.5 rockers = 510 lift; cc305 w/1.6 rockers = 544 lift. If you go with the 1.6's you need springs that can handle it. LT4 springs are only good to 525.
2) How high you will be revving.
3) how much safety precaution you want in your springs