hey, i bought a ls1 corvette motor a couple of weeks ago. it has 306 heads on them. i have a set of 862 5.3 heads that are shaved .030 sitting in the floor of my buddy's shop. should i use the 862s or the 306s. my truck is a 2000 rscb silverado.

 

306 because the bore on the LS1 is bigger than the bore on your 862 castings. they will flow better too.