Looking for suggestions 98 K1500 blown motor.

JonBoy

Active Member
Joined
Mar 20, 2005
Location
Hampstead NC
Truck has 235k miles 5.0/305 with manual trans 4x4. Front right fender has been half ass replaced by me, and I have also swapped rear ends from a 98 Tahoe with approx 145k miles on it. Interior is OK but seats are bad and need some attention. I would also say rust is very minimal and has new tires. I am on a very limited budget and looking for opinions. If I were to go looking for replacement it would be in the $3000 to $4000 range. Should I just put that into my current truck instead or buy a car? Opinions Welcome. I could see this being a decent project truck in a way.
 

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Describe 'blown motor'.

How long do you think you are going to keep the truck? Is this your DD? I'd be tempted to rebuild the motor myself on the cheap.
 
Depends on what is "blown". If it is just a head gasket with no overheat, I would rebuild it myself. Still cheaper to buy a head or 2 than to buy a whole new engine as long as the block is good.
 
I'd say "no" to a 305 head on a 350, every one of these motors I've seen tended to run hot, ping under load, require 93 octane no matter what and the smaller 305 valves would cause them to have excellent bottom end and then promptly fall flat on their face about 4000 rpm.

My choice would be to find a 96-99 5.7 Vortec in good condition from a running truck/burb/Tahoe/Yukon/van along with the pcm for it. make sure it has good oil pressure. While you have it out, definitely change the head and intake gaskets-these are notorious for having problems over the long haul, but fel-pro makes a better design that gm started using as a replacement years ago. Use the injectors from the 5.7, or if you have the cash, swap to the 2000& newer 5.7 vortec spider assembly found in vans, it's much more reliable. exhaust manifolds and sensors should be a bolt up. the wiring harness should be plug and play, the only thing i'm unsure of is if the pcm will set a fault code going to a manual trans, you may need to have the pcm programmed around this, there were no 1500's that came with a 5.7 and 5 speed. overall, it should be relatively inexpensive and gain close to 40 hp and 50ft/lbs of torque. be careful of future mods, as the 5 spds will break from excessive torque if you get too happy on the skinny pedal with a 5.7
 
It is my daily driver, I have owned it for 10 years and if I start dumping money into it the idea is to keep it for a long time. I have thought about rebuilding it but its already pissing me off just trying to pull the oil pan. Just lack of knowledge and proper tools. It sounds as there is something loose jumping around in the motor. I haven't gotten the oil pan off yet but would guess I broke a connecting rod. It does start and seems to be running fine but as things took a turn for the worse it got extremely hard to start like something was binding up.

At idle it doesn't make to much racket but hit the gas and things take a big turn for the worse. Still has oil pressure and no coolant in oil.
 
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My daddy had a 75 chevy van with a 350 in it that we drove to South Dakota every year. One year it cracked a head on the way home. When we got back, we put 305 heads on it and ran it for 5 more years hard. I got in trouble in HS for doing burnouts in the parking lot in that van. It. Is still running strong to this day.
 
I would really love to have a 350 but I am starting to think I should just stick with the 305 and with the money saved updating other areas of the truck. Possibly ordering a motor from Jegs soon. Need to talk to some local mechanics before ordering.
 
The last crate motor I bought was 1500 bucks out the door, so I know you can still find them for good deals. I'd keep the truck and definitely go for a 350. There's no reason not to, really. 45 more cubic inches and they're identical, so no problems with fitment.

You could always swap in an LS motor too! :D
 
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