98 5.7L vortec bad motor questions

[Nick1450]

My dad sold me his 1998 k1500 ext. cab about two years ago. I want to keep this truck long term as my driver and just replace the parts as they go bad or I have the funds.
Well the 5.7L just blew and I’m not sure if I should get a rebuilt motor and just replace it or get an Ls1/Ls2/Lq4 and make the swap. If I go the LS route, which would be the best for a budget build? I know I need the harness,and headers to fit, I believe my fuel tank and injection will work with most Lsx?

I’ve got about $4500 to my name, is a swap realistic with this budget? The trucks got 229k on it, the 4L60E has never been rebuilt. If I go with another 5.7 I could probably squeeze a 4l80e in the budget. Would it be a bad idea to swap to LS now and change the trans out later? I plan on keeping this truck in the long run and I’m going to tech school for welding in a few months.

Sorry about all the questions. I just need some advice on my next step with a truck I love and want to keep forever.

 

[94burbk1500]

That's a tight budget, but I think it is possible if you do your own work, pinch your pennies, and don't mind junkyard parts. At that many miles, I think it would be a pretty big gamble putting a new, potentially more powerful, motor in front of the original trans. I've not swapped an engine in a GMT400, so I can't speak to the overall difficulty, but you should always expect surprises when doing something other than an OEM replacement.

 

[Nick1450]

That's a tight budget, but I think it is possible if you do your own work, pinch your pennies, and don't mind junkyard parts. At that many miles, I think it would be a pretty big gamble putting a new, potentially more powerful, motor in front of the original trans. I've not swapped an engine in a GMT400, so I can't speak to the overall difficulty, but you should always expect surprises when doing something other than an OEM replacement.

Hey, thanks for the reply, I actually just got a loan from a family member so I now have $4500. Does this make it a more viable option?
I’m just torn because I don’t want to put money into rebuilt 350 if it’s going to break again soon but I don’t how much more it’d take to do the lsx swap right.

 

[94burbk1500]

Hey, thanks for the reply, I actually just got a loan from a family member so I now have $4500. Does this make it a more viable option?
I’m just torn because I don’t want to put money into rebuilt 350 if it’s going to break again soon but I don’t how much more it’d take to do the lsx swap right.

Obviously more money is always better, but I'd have to leave that question to someone with experience swapping the engines in these trucks. The big variable is how cheap you can find a motor, or motor, ecm, harness, etc, if you go for the LS option. If you're looking at a new long block, you're budget is damn near shot right there.

 

[Nick1450]

Obviously more money is always better, but I'd have to leave that question to someone with experience swapping the engines in these trucks. The big variable is how cheap you can find a motor, or motor, ecm, harness, etc, if you go for the LS option. If you're looking at a new long block, you're budget is damn near shot right there.

Yeah Im hoping to find a wreaked one or just a complete pullout around 100-130k. If I can’t do that I’ll just order a new 5.7L I guess.
If anyone has experience with LS swaps I’d love to hear your opinion. Especially in regards to rewiring the harness. I know you can get the standalone computer that integrates with my current system. Would it be worth shelling $500 out for one? And would the truck run smooth?

 

[94burbk1500]

Yeah Im hoping to find a wreaked one or just a complete pullout around 100-130k. If I can’t do that I’ll just order a new 5.7L I guess.
If anyone has experience with LS swaps I’d love to hear your opinion. Especially in regards to rewiring the harness. I know you can get the standalone computer that integrates with my current system. Would it be worth shelling $500 out for one? And would the truck run smooth?

This place is rife with LS build threads, there's tons to read about what they did, right or wrong, and how things turned out. If done properly, the truck should run just like a newer truck in regards to the engine itself. I know Lextech on LSforums can help you with the wiring and Black Bear Performance makes good tunes and whatnot for the LS motors.

 

[94burbk1500]

If this is your daily driver, replacing it with an identical motor is going to be the easiest and fastest route, maybe the cheapest too since you already have all of the accessories. If you have time to mess with it, LS all the way!

 

[L31MaxExpress]

IMO keep the Gen1 based engine and let the racers play with the LS engines.

I put a stock LQ4 6.0L/4L80E into a 1987 G20 van because I had the engine laying around. My brother drives it on road trips. It runs well but not as well as a lightly moded Vortec 350. Vortec 350 has more torque than a 6.0L up until the 3,500-4,000 rpm range. The only time that engine is actually fun and makes useable power is in the 3,500-5,500 rpm range in 1st and 2nd gear. The LQ4 has shorty headers that were required for clearance, dual 2.5 to single 3.5" exhaust, a TBSS intake, a CAI setup, electric fans, and PCM tuning. With 3.08 gears and 27.5" tall tires it gets about 17-18 mpg @ 70. I pulled a 20 ft dual axle car hauler with a small Kubota tractor weighing about 8,000 lbs total behind it and it was foot to the floor in 2nd gear up every little grade on the interstate to hold 65 mph. My 350 in the Express van pulls the same trailer up the same hills in 4th gear at 70 mph. 4.56 gears and 31.5" tall tires. 350 is turning about 3,000 @ 70, the 6.0L stays in the 4,000-4,500 rpm range uphill and turns about 2,700 in 3rd. My old 83 G20 was much stronger with its TPI Vortec 350 than the 6.0L van is.

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[shamrock246]

What went wrong on the original 5.7

 

[outlawten5]

On the practical side I would have the 5.7 rebuilt.