HELP!! Rebuilding or changing motor in 98 Chevy silverado k1500 4x4???

[axial 4x4 crawler]

Hello,
I have a 1998 Chevrolet silverado 4x4 k1500 ext. Cab and I am in a bind right know not just with money but what to do. So here we go, the truck has over 200,000 on it. The engine is a 5.7 350 ci. vortec efi and it has been leaking oil a little bit ( mostly from cold weather and not driving it as much; the seals crack from the cold). this truck has a newer transmission only with 30,000 on it but the motor has a lot of wear and tear. The orginal owner did a lot of trailer pulling with this and he took great care of it, and so do I but im thinking of a new engine. Or just rebuild the entire engine (cam-shaft, pistions, etc.). I wonder if they still sell a 5.7 efi vortec from GM in a "crate," Ill ask my dealer that!

My other option is a new Chevy 350 crate engine that is High performance and put out 365 hp (stock hp is 280) but this has a carb on it so changeing a efi truck to carb is it worth it to do that? The trans. should work with the other 350, but the headers will not. Don't worry Im not the type to offroad with or hotrod it I take care of it.(no offense to anyone). So tell me what some opinions are please, I would apperciate it. I sound stupid with this because I dont offroad with the truck, there is no telling when I can afford to do this. - axial 4x4 crawler

[redsawacs]

Rebuild it...when you rebuild it, you will need to bore the cylinders larger, this will increase HP and torque without trying. Not much but s little. A rebuild is at least 1/2 the price for a crate or production engine; short block or long block.

If you put a carbureted engine in it you will fight for fuel economy for eternity....don't do it. The OBD-2 computer system is a huge improvement over the OBD-1 and if you make it a carb truck, you will need to bypass a lot of computer controls to get the transmission to accept the donor transplant.

I can go on and on....

My recommendation, rebuild the long block and if you want to upgrade the crankshaft at that time, be sure to work the heads to accommodate the new "air pump control valve"(cam)

[axial 4x4 crawler]

Originally Posted by redsawacs

Rebuild it...when you rebuild it, you will need to bore the cylinders larger, this will increase HP and torque without trying. Not much but s little. A rebuild is at least 1/2 the price for a crate or production engine; short block or long block.

If you put a carbureted engine in it you will fight for fuel economy for eternity....don't do it. The OBD-2 computer system is a huge improvement over the OBD-1 and if you make it a carb truck, you will need to bypass a lot of computer controls to get the transmission to accept the donor transplant.

I can go on and on....

My recommendation, rebuild the long block and if you want to upgrade the crankshaft at that time, be sure to work the heads to accommodate the new "air pump control valve"(cam)

Ok I see what your saying about that, thank you. I will probably have the engine rebuilt. If I re-bore it too a larger ci. then it would be better then putting a new 350 in it. I can look at different crank-shafts and see what would give more HP and torque as you mentioned. Im going to talk to a mechanic this weekened at my dealer and see what they can do. With making it a larger cubic inch it may need more fuel supply??? Im sure there are plenty of after-market support for this but I have time to look at optional parts. You know what your talking about, another (as you mentioned) is tuning it with the computer, this can add even more power but also run efficently yes I will rebuild it sooner or later but Im curious to find out what Cubic inch it will be after they bore it larger (depending on what they do), it goes on and on with this kind of stuff but thank you very much for your reply, I appreciate it - axial 4x4 crawler

[WICKEDWOLFRC]

I had a 97 that i bought new for years....miss that truck every day! It started losing compression in cyl. 1 and 2 and it was time for a crewcab so I sold it. I looked into crates but they're pretty spendy and the hipo ones don't have much done to them. Keep the Vortec and rebuild it, throw in a hot cam and pocket port and polish the heads. That should get you close to 300 rwhp.

As far as boring it out, the HP and CI gains are minimal no matter how much is done the stock fuel supply is adequate.

For tuning I suggest Blackbearperformance.com Custom tuning is the only way to go and this guy knows his GM's I ran his Custom Autocal tune on my 03 6.0 and it really woke it up. He will tune it based on YOUR TRUCK not just a generic tune. I still have my Autocal just waiting on the aftermarket to get a bit more comfortable with the programming for the LML Duramax. Stay away from the out of the box tuners, I sell them all day long and most are garbage with the exception of the Diesel tuners.

[chino63]

How does it run? If it's running good, save some coin fix the leaks
and leave it alone.

My buddy picked up a 90 about a year ago with 230k on it for 1000. Leaking oil like a wet sponge, the previous owner thought it was a rear main and didn't want to spend any money on it. I found the oil cooler adapter o-ring was split. After a tune up, fixed the leak and an oil change, all was fine. Runs like a champ, he's currently getting 15 mpg.

[Big Tex]

slap a 383 in it and ftw!!! lol

[crash]

Buy a gm crate motor and be done. Get a good warrantee (you can install it yourself and any issues with it mechanically you can take it to any gm dealer)..

[WillieJ]

I would rebuild it. Fresh cam, pistons, and connectin rods. Have the heads redone and port and polish.