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5.7 Vortec in a 98 Silverado Z-71

2K views 8 replies 4 participants last post by  SilveradoKid 
#1 ·
I am buying a 98 Silverado Z-71 4x4 with 160K on the body & tranny, I think the original engine was the 5.3, or possibly the 4.8 - In either case, should I worry about the transmission handling the 350 ft/lb or torque versus the 305-335 ft/lb of it's original engine? Your input is appreciated, thanks!
 
#2 ·
5.3L engine came out with the 99 new body style trucks, it was not used in a 1998 truck.

The engines for 98 were
5.7 V8
5.0 V8
4.3 V6
 
#4 ·
hello the 5.7L had 4 o2 sensors and the 5.0L had 3 o2 sensors on the exhaust. This also was my debate on when i put a engine on my truck if the 5.7 would work but i think you would have to change the 02 senzors for the computers to make the truck run right
 
#5 ·
SilveradoKid said:
Ok, so lets say it was either of the smaller options... probably the 5.0, is the extra torque from the 5.7 going to be a problem on the tranny, or did they use the same tranny on both to begin with?
Same trans for both V8's.

There is a RPO Label in the glove box with the original engine and trans codes, look for anything beginning with an L for the engine codes, L05 for instance. Trans code begin with M, axle codes begin with a G.
 
#8 ·
It might be the original engine size, but the guy I'm getting it from put a new engine in it built by a local engine/machine shop. I just assumed he went the biggest he could and I also thought the 1500 only went up to the 5.3 so I guess i'm way off but either way I think it's gonna be a great truck! If all goes to plan I'll be picking it up on Saturday.
 
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