'98 Vortec into a '88 K2500, retaining the TBI

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Firewood truck

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Hello everyone,

I've been doing my due diligence by reading all that I can find on the topic, quiet a few threads have popped up with a ton of solid tech information. A quick summary of what I need to do: my '88 K2500 needs a heart transplant. IN October I did a HC test, the fluid turned green almost instantly. The engine urinates oil from every place that it could possible leak oil out of. I get the tell tale smoke generator from the tail pipe after starting it up and it runs for a few minutes. Since the engine would have to come out to reseal it and the heads need to come off and get checked for cracks, I started looking for alternatives. I've found a few low mileage '98 Vortecs locally, one of them stands out as a factory warranty replacement crate engine that only has about 55K on it.

The 1st thought was to use the Vortec as a short block, have the TBI heads rebuilt and use the TBI upper end. Once I started reading through some of the info in here, it started to seem that it isn't quiet as simple as that, so the next idea is to use the Vortec as a long block, use a carbed aftermarket intake and a TBI adapter plate. Not such a great idea after seeing that none of the aftermarket intakes have EGR provisions. The "correct" intake from GM Performance would make life easier, I'm simply not spending $700 for an intake. So now I'm back to the other 2 options- Vortec short block, TBI top end or Vortec long block and some sort of carbed intake w/ an adapter.

I'd like to hear from anyone who has actually done one of the Frankenstein conversions to hear pros/cons of each way of doing it.

I'm not interested in spending the $$ to drop off the current engine at a local machine shop and picking it up when it's done. I don't want to spend that kind of $$ for this truck- it's not that nice of a truck but after all of the work that I put into last year to get it running/road worthy, I need to get some more use out of it.

Thanks for any replies!
 

Firewood truck

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full


I decided to pull the core support and yank the engine/trans out that way.

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Out of the chassis, what a PIA to do by myself.

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L31 slowly getting prepped to go back in. Holley cast aluminum cover was cheaper then a OE plastic one, no brainer for that decision.

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L31 is a 4 bolt main, that was a nice surprise.

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new-to-me NV4500. I tore it down as far as I could, everything seemed to be in great condition. I replaced a few seals and the front bearing retainer.

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The 1st minor obstacle- the throttle cable bracket doesn't fit onto the vortec intake. I have a plan for an easy modification, but I need to source some stand-off style bolts to replace those 2 corner ones.
 
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Schurkey

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That block appears to have provisions for the coolant bypass/TBI-style water pump. You'd have to lift the right cylinder head off the block to drill one hole in the cylinder head deck surface to make the coolant bypass functional.

OR...

...Excellent candidate for a TBI-heads top swap, which then eliminates the EGR and intake manifold/bracketry problems.

My experience has been that the blocks having the coolant bypass drilling, also have 4-bolt mains and drilled engine-driven fuel-pump accommodations.

It'll never be easier to remove that block drain plug, clean out the drain hole, and replace the plug with a brass 1/4" NPT plug...or a brass draincock.

What's with the discoloration around the Holley timing cover?
 
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HotWheelsBurban

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That block appears to have provisions for the coolant bypass/TBI-style water pump. You'd have to lift the right cylinder head off the block to drill one hole in the cylinder head deck surface to make the coolant bypass functional.

OR...

...Excellent candidate for a TBI-heads top swap, which then eliminates the EGR and intake manifold/bracketry problems.

My experience has been that the blocks having the coolant bypass drilling, also have 4-bolt mains and drilled engine-driven fuel-pump accommodations.

It'll never be easier to remove that block drain plug, clean out the drain hole, and replace the plug with a brass 1/4" NPT plug...or a brass draincock.

What's with the discoloration around the Holley timing cover?
Looks like silly cone , smeared, to me.....
 

sntrym

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Hello everyone,

I've been doing my due diligence by reading all that I can find on the topic, quiet a few threads have popped up with a ton of solid tech information. A quick summary of what I need to do: my '88 K2500 needs a heart transplant. IN October I did a HC test, the fluid turned green almost instantly. The engine urinates oil from every place that it could possible leak oil out of. I get the tell tale smoke generator from the tail pipe after starting it up and it runs for a few minutes. Since the engine would have to come out to reseal it and the heads need to come off and get checked for cracks, I started looking for alternatives. I've found a few low mileage '98 Vortecs locally, one of them stands out as a factory warranty replacement crate engine that only has about 55K on it.

The 1st thought was to use the Vortec as a short block, have the TBI heads rebuilt and use the TBI upper end. Once I started reading through some of the info in here, it started to seem that it isn't quiet as simple as that, so the next idea is to use the Vortec as a long block, use a carbed aftermarket intake and a TBI adapter plate. Not such a great idea after seeing that none of the aftermarket intakes have EGR provisions. The "correct" intake from GM Performance would make life easier, I'm simply not spending $700 for an intake. So now I'm back to the other 2 options- Vortec short block, TBI top end or Vortec long block and some sort of carbed intake w/ an adapter.

I'd like to hear from anyone who has actually done one of the Frankenstein conversions to hear pros/cons of each way of doing it.

I'm not interested in spending the $$ to drop off the current engine at a local machine shop and picking it up when it's done. I don't want to spend that kind of $$ for this truck- it's not that nice of a truck but after all of the work that I put into last year to get it running/road worthy, I need to get some more use out of it.

Thanks for any replies!
I did the TBI to Vortec swap a few years back. I used the GM intake initially. I picked one up gently used and it worked great. I've since swapped heads, cam, and went to a carb intake with a square bore to TBI adapter. EGR has been tuned out since the initial swap.

The initialy swap was a pain in the ass honestly. I got a bit more power, but the extra work to move stuff around and modify/fabricate brackets was a pain. The Vortec intake mounting bolts are vertical, the TBI are not. So you need to bend stuff, drill, etc. I would not do another straight TBI to Vortec swap.

My recommendation is either get a TBI long block and drop it in there and go, or get an 880 short block and build something with a bit more kick and have it tuned.
 

Firewood truck

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After spending too much time this morning running around trying to find the 3/8-16 flange head bolts to reinstall the exhaust manifold, I had to buy 2 1/2" bolts from 2 different places, then cut them down an chase the treads. The manifold finally went on so I moved on to rebuilding the old motor mounts. I had a guy at work run them through the blast cabinet. I rattle canned them yesterday. I bolted them together today then welded them together. Good enough.

I'm not very happy at how sloppy the long engine mount bolt fits through the mount, it's a very loose fit. I was expecting a better fit from Energy Suspension.
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