Replacing Blown Motor, 5.7... suggestions?

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JeremyNH

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Well, I don't know much about engine specs, doing this on my own. I would love to get a better, more powerful engine than the 5.7 I have. Not sure what is involved with transferring the top end over as you said. If I were to get a HT383 and 395 cam, do I just unbolt my tbi and bolt it into the 383? Excuse the stupid questions... the in depth stuff such as this is out of my league but I'm trying to make it work. Thank you for your help!!! And everyone above as well!
1998 is vortec not tbi. If you have a vortec then you need a cam and transfer over the heads and everything attached to them since there is no difference between what you have and what the HT383e new has except that your parts are seasoned. Basically get the HT383 short block, put it on a stand, and other than the cam everything on your L31 that isn't on the short block transfer over, then reinstall the new motor, plug it in, get a tune, and enjoy. That's my plan if I ever decide to ditch my L31.
 

GoToGuy

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If, if you want to do a short block or a long block. If you want to on the road sooner and can afford it, opt for the more complete engine.
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NW4x4Chevy98

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1998 is vortec not tbi. If you have a vortec then you need a cam and transfer over the heads and everything attached to them since there is no difference between what you have and what the HT383e new has except that your parts are seasoned. Basically get the HT383 short block, put it on a stand, and other than the cam everything on your L31 that isn't on the short block transfer over, then reinstall the new motor, plug it in, get a tune, and enjoy. That's my plan if I ever decide to ditch my L31.
The 383 is appealing for sure. Nothing but good things about it, but I'm pretty sure my heads will at least need to be serviced etc before installing. So... anywhere I can get the full 383 with heads and 395 cam as a package? Ditch all my old seasoned parts...?
 

JeremyNH

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The 383 is appealing for sure. Nothing but good things about it, but I'm pretty sure my heads will at least need to be serviced etc before installing. So... anywhere I can get the full 383 with heads and 395 cam as a package? Ditch all my old seasoned parts...?
You can get a full HT383e. GoToGuy posted the pic. $6300. HT383 short block is $4300. I already have the 395 cam in my L31 so my plan is short block and transfer if I ever do choose to upgrade. But most people with the HT383e get the full crate motor.
 

Schurkey

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While I understand you need some guidance--and preferably an on-site mentor--I'd really hate to see you replace an entire engine because you've maybe got one broken valve spring.

MAYBE the valve is seized in the guide; or bent. Maybe it's not as simple as a popped valvespring--which would be really easy to replace.

Point being, I'd like to see more diagnosis of what's actually wrong.

OTOH, GM sells the emissions-legal 383 engine package, you'd re-use little from your existing engine. Intake manifold/injection spider, and all the accessories--alternator, ps, A/C compressor, exhaust manifolds, etc. Everything you re-use needs to be inspected. Common for the exhaust manifolds to be cracked, for example.
 

NW4x4Chevy98

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While I understand you need some guidance--and preferably an on-site mentor--I'd really hate to see you replace an entire engine because you've maybe got one broken valve spring.

MAYBE the valve is seized in the guide; or bent. Maybe it's not as simple as a popped valvespring--which would be really easy to replace.

Point being, I'd like to see more diagnosis of what's actually wrong.

OTOH, GM sells the emissions-legal 383 engine package, you'd re-use little from your existing engine. Intake manifold/injection spider, and all the accessories--alternator, ps, A/C compressor, exhaust manifolds, etc. Everything you re-use needs to be inspected. Common for the exhaust manifolds to be cracked, for example.
Yeah I do agree, I am currently taking everything apart and inspecting the engine. My problem is, if I'm breaking everything down, why wouldn't I rebuild it, especially after 300k... so do I dump money into this engine? Or find a replacement. And my luck (which is less than ideal) is that its not just a valve spring. But, I will keep this thread updated when I find out more. My other issue is I am doing this on my own with no one to actually hands on help me and say "oh see, right there is your issue and this is how to fix it." I've never measured depth on springs and never torn into the heads or fixed valve springs, so I'm for sure uneasy about doing something wrong and making things worse. But, these trucks are a passion of mine and beautiful. When it ran, so many compliments from random people... needless to say, its very important I get it going again. I really do appreciate this forum and all the helpful people.
 

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NW4x4Chevy98

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Point being, I'd like to see more diagnosis of what's actually wrong.
It started with a cylinder 3 misfire code. Accelerating up a hill started a heavy knocking and when I pulled over it completely died. Trailered back to the house, it won't stay running under its own power. Sounds terrible. So I removed the valve cover and the only thing I could see thus far was one of the rods and lifter was extremely loose, flopping around... pulled the rod, checked to see if it was bent, no bends that I could see even rolling on a flat surface. So I was told the best thing to do is remove the head, which... is a lot for me. No shop... snowing... the whole 9. But I have started the process of removing the heads to see if it is a stuck valve. Or worse... sound proper?
 
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Schurkey

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I would have tried a cranking compression test, and a cylinder leakdown test BEFORE removing the cylinder head.

If you tap (not "beat") the "short" valve with a plastic-tip hammer, does it move, or is it jammed in place?
 

GoToGuy

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Why is it not at full height ? Broken valve spring - loose spring, valve stem bent jammed in guide- compressed valve spring. Short spring- valve face bent not seating. You just had misfire, any knocking, no oil pressure issues?
 
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