1998 k1500 5.7 rebuild or replace

Tracto-man · March 24, 2019

My trucks nearing 350k miles on a stock 5.7 motor, and it's starting to show. Little bit of oil usage, oil pressure usually around 17-20psi hot at 1600rpms, but mainly just noticing significant power loss within the last 45k miles or so, gets on the highway like a 2.0, lol. I know the truck probably isn't worth it to spend the time and money of a new motor, but it's worth it to me. So I'm wondering what the general consensus is on rebuilding the Motor that's in it, versus buying a crate motor, versus buying a lower mileage used 5.7. And wondering what anyone else who's done this ran into, probably would want new alt, starter, water pump, ps pump, etc etc? What did you run into that you wished you just replaced?

I would like to do some simpleish power upgrades too, nothing crazy like a hot rod as it gets used everyday, but more power is always better. And then the other issue is that since it's a old truck, I'm not trying to cheap out but I'm not going to go blow 3k on a motor either. Along with the motor, maybe regearing diffs, and rebuilding the front end, I'd like to keep it around 3-4k total. I know it's not worth but the trucks lasted so long with minimal issues while I beat on it it's time to "make it nice again", lol. In the end it's not unlikely that it will be loosing the body lift and getting a 6-10in suspension lift and some nice new shoes?

wreckdiver230 · March 25, 2019

my preference is to rebuild myself if i have time , money , place to do it will all tools, and of course skill, if you want to save money good used engine would work , but would you be happy with that. you have alot of options , many speed shops are selling performance crate engines now

Mikebtte · March 25, 2019

47 minutes ago, wreckdiver230 said:

my preference is to rebuild myself if i have time , money , place to do it will all tools, and of course skill, if you want to save money good used engine would work , but would you be happy with that. you have alot of options , many speed shops are selling performance crate engines now

I am with Brian. You could swing in a used engine for cheap. Myself I would do a rebuild. Check the block and if its good you can install some new pistons and rings and reassemble. Maybe step up your cam a bit and you will be in it very cheap. Worst case you would need to have it board over and add oversized pistons. If it needs more than that you may need a used engine.

If you have a shop do the rebuild you could end up spending money real fast and go over budget quick.

5.7 Vortec is a good engine, a mild cam (small enough to not affect the ECM) and nice internals would wake up the old truck.

alpinecrick · March 26, 2019

A guy can have a brand new L31 Vortec delivered to his door for less than $2100 from Scroggin-Dickie. Another $500 for gaskets, new motor mounts, sensors, etc.

The cost of a full rebuild of your existing motor is a LOT more than that. Even rebuilding it on the cheap ain't all that cheap, and no guarantee it will be much better than what you have now.

In other words, a good, strong engine would come first, long before a lift and fuzzy dice...................

wreckdiver230 · March 27, 2019

nothing comes before fuzzy dice

alpinecrick · March 28, 2019

9 hours ago, wreckdiver230 said:

nothing comes before fuzzy dice

I know, I know.......:)

flyingfool · April 1, 2019

get a GM L31 drop in motor , install z28 cam and springs, z28 oil pump, and 1.6 or higher rocker arms. 3300hp on a SB chevy non-LS swap bullshit! total cost $2500

I have a 2016 silverado and wish I would of just rebuild an old truck, the new tech just sucks! my 2016 cost me $365 a month just to cover ; fuel , insurance, and registration for the year. And i paid $38,000 for it.

Edited April 1, 2019 by flyingfool