how can you tell the difference between a 4.8 and 5.3 motor
#22
Launching!
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Thats most likely a 4.8l. You can tell by the different rod casting numbers. Or since its already down to the shortblock, just measure the stroke roughly by rotating a piston to bdc and stick a tape measure down the cylinder. Itd be roughly 3.6 in. for a 5.3, and roughly 3.25 for a 4.8l. I accidently bought a 4.8l before doing the neccesary research.
#28
One of the heads is cracked. My 4.8 looked just like that and it had a cracked head. Causes crankcase pressure to build up faster than the pcv can keep up and chuggs oil into the pcv valve through the driverside valve cover. I bet the intake was full of oil wasnt it.
#34
TECH Resident
Absolute truth. I myself have put more than one low mileage $350 junkyard 4.8 in a 5.3 truck I was flipping! I have also found a 4.8 in a truck that was supposed to be a 6.0L! Throwing a cheap engine in a truck to get it back on the road is not really unusual on a 10+ year old truck.
#38
TECH Senior Member
Depends if the 4.8 is Gen IV or III. Where are the knock sensors and cam sensor?
Within the same generation it's a direct swap
Within the same generation it's a direct swap