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Discussion Starter · #1 ·
Alright.... I'm new to to the forum scene and I need some help....
I've bought a '99 Tahoe 5.7L Vortec 4WD few months ago from an auction with 197,xxx on the odometer.
It ran a little rough but I gave it a tune up, drove it about 5,000 miles and It just ***** the bed with both heads cracked.
Now my question is.... Would it be ok to just slap a set of rebuilt heads on the 200k mile block and call it good?

The heads that came off of it are "12558062"
I do have a good set of "14102193" heads that come off a 1994.
Would they work on my Tahoe?

Any advice would be greatly appreciated. Thank you.
 

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Alright.... I'm new to to the forum scene and I need some help....
I've bought a '99 Tahoe 5.7L Vortec 4WD few months ago from an auction with 197,xxx on the odometer.
It ran a little rough but I gave it a tune up, drove it about 5,000 miles and It just ***** the bed with both heads cracked.
Now my question is.... Would it be ok to just slap a set of rebuilt heads on the 200k mile block and call it good?

The heads that came off of it are "12558062"
I do have a good set of "14102193" heads that come off a 1994.
Would they work on my Tahoe?

Any advice would be greatly appreciated. Thank you.
The 193 heads won't bolt to the intake and have exhaust heat cross over passages that would fry the plastic intake if it did.

Cracked heads are a good indicator that the engine was toasted somewhere in it's history, they are scrap. These heads are available rebuilt on Ebay and other places at resonable costs, new factory heads are available resonably priced. The after market has versions in aluminum and iron that are better than the factory heads and much less sensitive to heat induced cracking than the OEM heads.

Bogie
 

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Discussion Starter · #3 ·
oldbogie I appreciate the prompt response...
So that being the case where the intake doesn't match the 193s, what would need to happen in order to put the whole engine from the 94 into my 99? Change harness and computer?
 

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For everything you would need to do you would be better off rebuilding the original and sourcing some replacement heads.
Putting new heads on a tired engine usually results in lower end failure not long after
 

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oldbogie I appreciate the prompt response...
So that being the case where the intake doesn't match the 193s, what would need to happen in order to put the whole engine from the 94 into my 99? Change harness and computer?
Sorry, really not compatible in any practical way. If you want to keep the 99 you need an engine that the correct fuel injection system will bolt up to. hcompton gave you a good link. Unless you are very techically adept, you will never successfully complete a 94 TBI into 99 Vortec swap using factory parts.

You could always carburate it and retain the 99 computer for trans shifting, but that would be rinky dink IMHO - and what worse engine to spend money and effort to swap to.......

A small block Chevy is not universal anymore. But I found that to be true with the old ones too. A 1966 327 does not fit in a 1970 Camaro if you want to use the factory A/C and P/S. I once put one in and subsequently found no holes in the heads to mount the same. Lesson learned.
 

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oldbogie I appreciate the prompt response...
So that being the case where the intake doesn't match the 193s, what would need to happen in order to put the whole engine from the 94 into my 99? Change harness and computer?
As has been indicated that is a tough row to hoe, but not impossible. The big issue is the 99 chassis and driveline is very married to the computer that also runs the Vortec unique EFI. The 94 is the much simpler EFI that is known as Thottle Body Injection (TBI) which it and the chassis and drive line of the 94 is very much different in the details of how the systems integrate and function. So it is very much simpler to keep the 99's injection system which doesn't bolt to the LO5 Swirl Port heads.

The bottom end of the 94 can be modified to accept the 99's crank sensors with a change to the 99's timing cover its attached sensor plus the unique L30/L31 crank damper, and the unique L30/L31 distributor. But the 94 cam is a flat tappet that is very mild and not close to the timing of the 99's roller cam. Some 94 blocks are provisioned for a roller either partially to fully machined which would let you transfer the 99's cam and valvetrain. But if the block is not provisioned you would need to install a cam similar to the old 929 300 horse cam or Edlebrock sells a similar cam with shorter ramps but with similar .050 timing to the 929 which is more compatible with EFI. However after all that you still have to go with the 96-2000 style head used by the L30 and L31 engine so it will accept the bolt pattern of the EFI intake and injection system.

All that said unless the 99's bottom end is shot it would be a lot simpler and cost effective to replace the L31 heads either factory or aftermarket or if the budget allows use an L31 crate engine.

Bogie
 
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