Author Topic: 1991 Crew Cab Going 6.0 LS  (Read 6952 times)

Offline ehjorten

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1991 Crew Cab Going 6.0 LS
« on: November 29, 2016, 03:54:14 PM »
Picked-up a low mileage 6.0L LS out of a 2004 Yukon Denali XL2500 today! Slightly different route now. Hope I will be satisfied. I don't think I'll be making 410 lb-ft of torque at 1,600 RPM anymore! I'd really like to put some L92 heads and an LS3 intake manifold on it, but the cost of those things along with a new camshaft really isn't in the cards right now.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=19098.msg290063#80
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Captkaos

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #1 on: December 05, 2016, 11:14:39 PM »
I would run the factory Truck intake.  That should be a LQ4 which makes 300hp and 370lb/ft.

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #2 on: December 07, 2016, 10:41:35 AM »
For those that don't know...the 1991 V3500 came from the factory (only year for the 3rd Generation trucks) with a 4L80e and a NP205 transfer case with VSS.


My 4L80e does not have the top center bellhousing bolt that was added in the LS block and my 2004 LS block does not have the upper, passenger's side bolt hole!  It has the pad that looks like there should be a drilled and tapped hole though.

My question is...can I just drill and tap that hole in the back of the engine block to get my missing transmission mount back?
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Captkaos

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #3 on: December 08, 2016, 07:43:48 PM »
Don't waste your time.  My truck isn't running that bolt...

Chris Lucas
73-87chevytrucks.com
squarebody.biz


Offline Irish_Alley

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #4 on: December 08, 2016, 10:45:03 PM »
so how many bolts does yours have capt? 5? ive seen some run just 4 on the carb motors
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Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #5 on: December 09, 2016, 09:57:45 AM »
Consensus seems to be that you don't need that 6th bolt...just leave it out.  I did find out that if you drill that pad out you will hit one of the head bolt holes!  I heard from a guy that said he drilled his out about 18 mm deep and tapped it and got about 13 mm of thread.  In an iron block that would be enough, but in an aluminum block it would not!

I contemplated a SFI bellhousing, but that involves cutting off your bellhousing and the system costs about $500. http://www.ckperformance.com/View/4L80E-SFI-BELLHOUSING-ADAPTER-PACKAGE

I guess for now, I will just use 5 bolts and see what happens.  If I run into problems then I can go the Ultra Bell route.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Captkaos

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #6 on: December 10, 2016, 07:23:37 PM »
Mine has 5 bolts in it.  2002 6.0, 1993 4l80E, 31,000 miles.

Don't drill the 6.0 block...

Chris Lucas
73-87chevytrucks.com
squarebody.biz

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #7 on: December 12, 2016, 07:32:10 AM »
Got my Off Road Design's Crossmember mocked-in!  You have to drill-out one rivet hole and drill a couple of new holes in the bottom web of the frame to mount it.


I drilled and tapped a hole to attach the clamp for the front differential breather.  It was clamped to the old stock crossmember.


I also drilled and tapped a hole for the clamp that goes to the hardline.  It was also bolted to the old stock crossmember.


Then I pulled it all out and the engine crossmember, frame side motor mounts and the transfer-case crossmember are going to the powdercoater for a fresh coat of semi-flat black.
« Last Edit: December 12, 2016, 07:34:07 AM by ehjorten »
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline roundhouse

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1991 Crew Cab Going 6.0 LS
« Reply #8 on: December 22, 2016, 12:40:28 PM »
Got my Off Road Design's Crossmember mocked-in!  You have to drill-out one rivet hole and drill a couple of new holes in the bottom web of the frame to mount it.


I drilled and tapped a hole to attach the clamp for the front differential breather.  It was clamped to the old stock crossmember.


I also drilled and tapped a hole for the clamp that goes to the hardline.  It was also bolted to the old stock crossmember.


Then I pulled it all out and the engine crossmember, frame side motor mounts and the transfer-case crossmember are going to the powdercoater for a fresh coat of semi-flat black.
Looks good

I don't think the head and cam swap is worth the cost
Stock makes good power



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Offline frotosride

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #9 on: December 23, 2016, 01:51:01 PM »
Picked-up a low mileage 6.0L LS out of a 2004 Yukon Denali XL2500 today! Slightly different route now. Hope I will be satisfied. I don't think I'll be making 410 lb-ft of torque at 1,600 RPM anymore! I'd really like to put some L92 heads and an LS3 intake manifold on it, but the cost of those things along with a new camshaft really isn't in the cards right now.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=19098.msg290063#80

I like it... are you sure of which engine you got, LQ4/LQ9. If you don't have the VIN from the vehicle the only way to tell will be to pop a spark plug and look at the pistons. Flat tops would be LQ9 and 10.1 compression plus the small bump in power from the compression change.  As for the heads and intake change, I'd say go for it but you will also have to get a water pump for an '07 or newer truck and trim the alternator bracket, or get a complete FEAD system from a LS car.
I like the new Crossmember, may I ask why you decided to ditch the OE one?
"Beat it like a red-headed ford"
1987 v10 Silverado 4" RC, 35's, 700R-4, 3.73
2006 Boulevard M109R 109 cid, straight pipes, PCMlll,k&n
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Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #10 on: December 23, 2016, 07:36:19 PM »
The OE crossmember interfers with the oil pan on the driver's side.  You can notch the crossmember or you can put something like the ORD crossmember in.  It gives better clearance to the engine and also better clearance for my crossover steering.

And yes, I am sure of the engine that I got.  It is a LQ4 out of a 2004 GMC Yukon XL 2500 with 95k miles on it.  Full Drop-out in excellent shape!
« Last Edit: December 23, 2016, 07:40:58 PM by ehjorten »
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline ehjorten

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #11 on: December 23, 2016, 07:38:45 PM »
Side question...I am getting close to finding out, but does anyone know if the stock LQ4, low, passenger's side A/C pump will fit in-between my frame rails?
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline roundhouse

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #12 on: December 25, 2016, 03:23:47 PM »
Side question...I am getting close to finding out, but does anyone know if the stock LQ4, low, passenger's side A/C pump will fit in-between my frame rails?
It won't fit


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Offline roundhouse

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #13 on: December 25, 2016, 03:26:55 PM »
The OE crossmember interfers with the oil pan on the driver's side.  You can notch the crossmember or you can put something like the ORD crossmember in.  It gives better clearance to the engine and also better clearance for my crossover steering.

And yes, I am sure of the engine that I got.  It is a LQ4 out of a 2004 GMC Yukon XL 2500 with 95k miles on it.  Full Drop-out in excellent shape!
We have a 76 K-10 and instead of modding the crossmember or oil pan
We just put some 1 inch spacers between the motor mount on the engine  and the frame mounts

Raised it just enough that the pan would clear



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Offline Captkaos

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Re: 1991 Crew Cab Going 6.0 LS
« Reply #14 on: December 26, 2016, 04:25:18 PM »
Modify the location of the that side engine mount should make it work.