I got a buddy with a 89 sierra 1500 EC he wants to put a 5.3 in it, what all will he need in order to do the conversion?

 

Since the Gen I drivetrain shares little-to-nothing with the newer Gen III drivetrain, he is looking at a complete overhaul. The computer, wiring harness, engine and accessories are all different meaning he'll need to splice into his current harness or have one made to keep the gauges working properly. The transmission will not bolt directly up without a spacer, longer bolts, flywheel modifications and even then a few bellhousing holes will not be used. If memory serves, the motor mounts and fan shroud are different and if he has a 4wd he'll need to address the issue of making room around the front differential for the 5.3L oil pan or swap pans to a shallow mount LS2 pan (including windage tray & pickup tube) to clear the housing. The radiator will need a steam vent tapped into it and even then I don't think the hoses are the same size.

Bottom line, he's looking at an uphill battle the entire way. If the 98 is in good shape, I'd recommend selling it and getting a newer truck with a 5.3L in it already. If he sold the 98 for 4-5k, and bought a 5.3L truck for 8-9k, he'd probably come out ahead money since the 5.3L swap he's interested in is looking to cost 4k+ for a job done right.

 

thanks for the info... I'll let him know...is it really that much? we thinking maybe 2-3k...

 

There's swapping a motor, then there's doing it the right way so the motor and transmission last another 100k+ miles. I stopped counting after $7300 for my motor and transmission swap in my Sonoma, which has the same drivetrain obstacle issues as your buddy's 98.

GMPP has a pretty cheap 383 drop in V8 which will only need a tune if he already has a 350. That might be a route to investigate.

 

he's got the 5.0 TBI motor...