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99 Yukon L31 rebuild?
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Post 99 Yukon L31 rebuild? 
New to this forum.

99 Yukon 190k on the clock. Still runs well but seems exhausted if you will leaks oil like a sieve. Looking to get some extra kick for towing situations. Nothing radical - I think.

Engine is just about ready to come out of truck. Long story hopefully short explanation. Main brake line down side of frame rusted/wore through where it took a turn over the flange on the C channel just before the driver side wheel. Gravel guard most likely prevented it from wearing through earlier. Had to drop tank to actually see what really happened started the can O worms opening.Next to the fuel filter. Fittings of course froze up both sides of fuel filter so I made the call to twist them off and at the very least splice some hose to new fittings and a new filter. Did some searching for new pipes and was able to find both rear pipes off Amazon OEM stuff and a place called Pipes to Go for the front end pipes. Bought some rolls of brake line and remade all new lines up front 2 in the back and the main one that started this whole mess out. All worked out well.

Decision to pull the motor came when I was down there looking at oil leaks that I have dealing with for a few years that “seem” to be getting worse. So I made the call and un wired all harness connector drained radiator unbolted everything except the flex plate and 2 motor mounts.

What to do next. Crate motor from Summit through GM replacement or go locally with a builder and hope to sneak a bit more power and torque out of few mods in the process.

Crate motor is about $2100 vs $1800 rebuild for comparison.

Thanks in advance.

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anyone?

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if the local builder is reputable, go with him

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Does your local builder offer a warranty of any sort? That is something to consider versus a GM crate engine.

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Cheaper to do a LS swap

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That depends on where you are located. Around here a decent used LS engine will cost you almost as much as a rebuilt GEN I small block.

stroker97k1500 wrote:
Cheaper to do a LS swap


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Perhaps, but you get better mileage and more power, plus the LS engines are now better supported by the aftermarket than those old, discontinued engines.

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Wow... this forum isnt what it used to be. Imo the GM crate engine would probably be your best bet, if i had looked into one before i started rebuilding the L31 in my 99 yukon i would have went that route. Instead i rebuilt it and spent 3 months curseing the day i bought that damn truck, But then it started and all was good.

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To rebuild an engine cost a lot, and it doesn't always go well...

I'd go with a crate 383 short block and your oem heads (for $500 more than your 350 crate)

https://www.summitracing.com/oh/parts/hpe-sp15/overview/

(extra kick for towing)



Last edited by CrazyHoe on Thu Aug 31, 2017 5:02 pm; edited 1 time in total
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Use .045 gasket instead of .039 due to high compression

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CrazyHoe wrote:
To rebuild an engine cost a lot, and it doesn't always go well...

I'd go with a crate 383 short block and your oem heads (for $500 more than your 350 crate)

https://www.summitracing.com/oh/parts/hpe-sp15/overview/

(extra kick for towing)


IMO That's a good price for that, I wonder if you can get it made from a roller cam block?
Maybe some other heads like some aftermarket Vortec heads, then you can just sell your current used Vortec 350 heads and not have to rebuild them. The OEM 060 part number heads tend to be cracked in the valve seat area.

Summit brand Vortec's 175cc intake runner volume/tad larger 67cc chamber(which would help out on that shortblock if compression ratio is a concern) $349
https://www.summitracing.com/int/parts/sum-151124/overview/make/chevrolet

or the ProMax head 2151 with 185cc intake port volume with a stock 64cc chamber, these are an Asian made and assembled head, they do use the larger 2.02"/160 valves while the stock Vortec and the Summit Vortec use the smaller 1.94"/1.50" valves $765/pair
https://www.summitracing.com/int/parts/pmx-2151

The bare version of the above head I listed(2051) the bare head carries p/n 2050-$614
https://www.summitracing.com/int/parts/pmx-2150


For comparison the good old 12558060 OEM Vortec L31 heads, 170cc intake runner volume/64cc chamber $320
https://www.summitracing.com/int/parts/nal-12558060/overview/make/chevrolet

Then you get into the GM Bowtie Vortec heads The smallport versions 19331470 with 185cc intake runners/66cc chambers assembled with 2.00"intake and 1.55" exhaust valves $663 EACH.

Chev Performance Fastburn akuminum 19300955 $819 EACH come complete with 2/00/1.55" valves 210cc intake runner volume and 62cc chamber D-port exhaust like LT1/4 head This head is used on 425hp 383SP and was used on the older ZZ430/430hp 350 crate engines. These heads have been updated a few years ago, and now come with Beehive springs.
https://www.summitracing.com/int/parts/nal-19300955/overview/make/chevrolet

Then the AFR 190cc Vortec heads with 190cc intake runner size/65cc chamber p/n 0912 $1666 a pair Emission legal on Vortec trucks. This would be a great head on a 383.
https://www.summitracing.com/int/parts/afr-0912/overview/make/chevrolet


peace
Hog

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lucky 13 wrote:
Wow... this forum isnt what it used to be. Imo the GM crate engine would probably be your best bet, if i had looked into one before i started rebuilding the L31 in my 99 yukon i would have went that route. Instead i rebuilt it and spent 3 months curseing the day i bought that damn truck, But then it started and all was good.


Yeah, board's pretty much dead these days. I guess people like those flashy sites more than superior expertise. Except the superior expertise here is all over the interwebs now. Still, I at least prefer the simpler format of this site.

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Hog wrote:

IMO That's a good price for that, I wonder if you can get it made from a roller cam block?
Maybe some other heads like some aftermarket Vortec heads, then you can just sell your current used Vortec 350 heads and not have to rebuild them. The OEM 060 part number heads tend to be cracked in the valve seat area
.
Yes it is a roller cam block :

"Hello Robert, yes it does have OE Roller cam provisions, but it does not come with the plate."

Blueprint engines has a similar block but higher comp ratio

Hog wrote:

Summit brand Vortec's 175cc intake runner volume/tad larger 67cc chamber(which would help out on that shortblock if compression ratio is a concern) $349
https://www.summitracing.com/int/parts/sum-151124/overview/make/chevrolet


Those would be perfect since they have screw in stud and machining down the valve boss and going to beehives springs for bigger cam is a DIY job
9.8:1 with 64cc
9.55:1 with 67cc

Hog wrote:

Then the AFR 190cc Vortec heads with 190cc intake runner size/65cc chamber p/n 0912 $1666 a pair Emission legal on Vortec trucks. This would be a great head on a 383.
https://www.summitracing.com/int/parts/afr-0912/overview/make/chevrolet

Those are my choice if the budget allows it.

peace
Hog[/quote]

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Speeder wrote:
lucky 13 wrote:
Wow... this forum isnt what it used to be. Imo the GM crate engine would probably be your best bet, if i had looked into one before i started rebuilding the L31 in my 99 yukon i would have went that route. Instead i rebuilt it and spent 3 months curseing the day i bought that damn truck, But then it started and all was good.


Yeah, board's pretty much dead these days. I guess people like those flashy sites more than superior expertise. Except the superior expertise here is all over the interwebs now. Still, I at least prefer the simpler format of this site.


The experts have moved on as priorities changed over time. The GMT400 and the L31 are a thing of the past. Only a few remain. But the information contained in past treads is priceless.
I'm still here because my truck is work in progress.
The PhotoBucket blackmail debacle is a huge blow to this site.
Mad

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hello flickr.com

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Cant beat GM's pricing on crate motors. I just replaced the engine in my 1998 farm truck after 308K miles and a bad head gasket. Got a GM crate L31 Long block with GM 3yr warranty for $2,019 shipped to my door free! Cant beat that. Its all 100% new, no rebuilt junk either!

TJ

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