5.3 heads
I think another 5.3L casting number is 862 but really they dont flow anymore than 241/853 head in stock form. A slight bump in compression but not worth the price of head gaskets or bolts.
My 5.3 done by Bo flowed the following:
219 @ .600" lift (exhaust)
261 @ .500" lift (intake)
My intake valves are cut for better flow down low & these heads were ported specifically to flow within my 224/224 .581/.581 cams lift. So for me personally flowing good over .590" lift wasn't needed. If I change cams later I'll move up to a set of 243 heads from TSP. I also had Bo mill my heads .018" to even further increase my comp. I haven't had a single issue with these heads since the install over a year ago & I daily drive my car 300+ miles per week.



