Where do i have to go to get information about my heads by using my head casting #?

 

www.Mortec.com
They have just about every number listed for blocks, heads, cranks, ect...

 

What if the only casting number i've got is #862? All of the mortec numbers are 6-8 digits long

 

Those should be the the last three numbers. What they have listed for Gen.III:

12556743...99......325..........Gen.III, 5.3L, aluminum, truck, van
12558806...97-98...350..........Gen.III, "LS1", aluminum, 68cc
12559853...99-up...350..........Gen.III, "LS1", aluminum, 68cc
12559895...00-up...325..........Gen.III, Vortec 5.3L
12564241...00-up...350..........Gen.III, "LS1", aluminum, 68cc
12564243...02......350..........Gen.III, "LS6", aluminum

I don't think I've ever come accross 862's What are these from?

 

they're supposed to be from a set of 5.3 heads i purchased yesterday

 

N/M. Sorry about that...862's are '99-00 4.8/5.3L. I guess they just don't have them listed there. These should be your specs:

Combustion Chamber Volume: 61.15cc
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches

 

Thanks a lot man, i would have never found that

 

Not a problem