i wont be using the ac or power steering stuff from this motor, or the clutch fan, an alternative accesory drive setup may be in order, but in the interest of budget, may not.
the heads on this little guy are 862's... heres some pertinent data from my LS info dump thread...
viewtopic.php?f=69&t=10150Casting Number 706 and 862
Head: 1999+ 4.8L / 5.3 Liter Truck
Material: Aluminimum
Part Number:
12559862
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174
seriously, many many many people have run these wheezy heads on this puny 4.8 and exceeded the scale on the butt dyno, well into 600+ wheel horsepower, many of them with a couple years of active use (those guys show a restraint and control over the urge to go harder till it pops that i may not be able to exercise) other guys have "broke the knob" turning it up into the 4 digit club before modifying the heads (other than valvesprings) and the bottom end (other than a cam)...
in the interest of reaching my target horsepower with the least resistance possible, i will likely be carving up these little heads, they have a relatively small combustion chamber compared to other LS heads that gives me room for valve unshrouding and overall combustion chamber smoothing without being a great detriment to compression ratio (not that it wouldnt hurt to lower it). in reality i think most of my work will be done in the combustion chamber, then some skinnying of the valve guides, minor bowl touch ups (depending on what i see there) and an 80 grit pass to make an even texture and im done with these suckers... depending on the cost i may or may not have a valve job done on them...