Ok so I am trying to fined a 5.7 vortec engine and I havnt had any luck what year trucks did they come in ? I thought it was 96 to 02 or somthing like that but I want to the junk yard and pulled a motor from a 98 2500 and it was a 5.3 but when I looked it up it says they didn't make them till 99 idk but it would be very helpful if some one would be abel to tell me what year and maybe the vin number/letter for the motor. Thanks.

 

A 5.3 is a LS engine
A L31 Vortec engine looks like any other SBC with centerbolt covers
but has only 8 bolts holding the intake manifold on; not 12 like reg SBC.

1996–2003 Chevrolet Express/GMC Savana full-size vans
1996–1999 Chevrolet/GMC C/K full-size trucks
1996–1999 Chevrolet Suburban/GMC Suburban
1996–1999 Chevrolet Tahoe/GMC Yukon
1999–2000 Cadillac Escalade
1996 G-Series vans over 8,500 lb w/ 4L80E

 

That's what I thought I pulled the motor from a 98 gmc 2500 and it has the senter bolt valve covers but the bore is 3 3/4 in not 4

 

Post some pics.

Most likely explanation is the truck wasn't a '98.

 

So if it looks like a reg SBC ( not a LS engine) it is probably a L30;
the 305 Vortec engine also used in trucks
Bore is 95 mm, stroke is 88.4 mm.