marineusmc4

I started looking on craigslist for some 243 heads and found a set. guy is asking 450 for em. im gonna see if i can jew him down to 300-350. once i get a set ill prolly have them ported and polished.

dmelvin

iTrader: (8)

You'll want to mill them .027 -.030 to maintain your compression ratio; they have bigger combustion chambers than the stock 5.3 heads.

marineusmc4

im assuming if porting is removing material than milling is adding material? if i didnt mill them would it adversely affect anything?

Atomic

iTrader: (42)

No, a mill is a machine like a lathe. The acting of using it is called milling....also may be from the fact that material is removed in "mils" or 0.0001 increments.

In a mill, the part stays still and the cutter bit rotates. In a lathe, the cutter bit stays still and the part rotates.

marineusmc4

gotcha. so milling a head decreases compression ratio and porting a head increases, am i understanding this right?

HuskerZ71

Milling I beleive would increase compression. Porting refers to removing material from the ports, around the guides, etc.

Area47

going to try and break 300 in this thing to day.

dmelvin

iTrader: (8)

Milling increases compression. Essentially, you're taking a knife and shaving the entire mating surface of the head, with each pass, you're taking a little material. As you do this, it makes the combustion chambers smaller, therefor increasing compression.

marineusmc4

Gotcha. Is ur truck 2 or 4wd?

05chevy04yfz

good thing i seen this im getting ready to put a maggie 112 on my 06 ss and want to have it tuned in person. not going to use justune for sure. Area 47??? want to tackle it in the furture?