4.8/5.3 genIII question?
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Teching In
Joined: Dec 2012
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4.8/5.3 genIII question? when you have the 4.8/5.3 block and casting number 12551358. from there how do you identify what size your running the 4.8 or 5.3 i know the blocks are the same but different stroke but do they have a number to show the size it is? thanks!
Launching!
Joined: Sep 2008
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From: Ashland,VA
on the rear of the block where it says "4.8/5.3" there will usually be a paint mark on or right above which ever one it is. If not try to look at the pistons. the 5.3 will have a dished piston and the 4.8 will be flat top pistons.
Launching!
Joined: Sep 2008
Posts: 234
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From: Ashland,VA
Thread Starter
Teching In
Joined: Dec 2012
Posts: 14
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it was out of a doner truck that was parted out im not 100% sure but 2003 0r 2004. its an iron block, my head casting numbers are 862, i have a 4.8 in my company truck witch have the same heads witch is making me feel its a 4.8. i did tear into the engine and i have the dished pistons with the plus sign looking marking on top. but then again some say that dosent matter, if i measure the stroke, what size should i have, the 5.3 should be longer than the 4.8 right? thanks again!
Yes it's weird alright ,,,,,,I can't believe GM not only made it hard to know which size but also those blocks were used for 5 or 6 years or more so the only way to know which year it is is to get #'s from almost every part in the engine and the PCM and look on here and Google ,,,,,,,,,blah blah ,,,,,pita
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Thread Starter
Teching In
Joined: Dec 2012
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yeah that is kinda shity, i wonder how many people bought a so called (5.3) thats really a 4.8 i kow i thought i did! haha that is kinda screwed up but im really in the market now for a 6.0 to get some responce out of my truck build!
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Verdad Gallardo I bought a what I was told was a 5.3L that turned out to be a 4.8L so the guy I bought it from gave Me a 5.3L and let Me keep the 4.8L so I've got some extra parts. So I spent alot of time porting a set of 706's then after just about finishing Them I find out there have been problems with many of the 706's leaking coolant so the other set I have are the 862's so I'm in the middle of porting those and that's ok because I've learned alot working on the others and learned more from LS1 Tech so the 862's will be quite a bit better .
