1998 k1500 6.0 4L80 swap

[Schurkey]

Perhaps a moderator will move this thread to LSX + Carb Swaps

 

[KevTemp]

Slide towards the radiator. For the fuel, it's been so long I can't remember where I got the fittings, but I went the expensive route.

This is an Earl's fitting that clicks on the rail.

GM 3/8" Fuel Line to -6AN Adapter - Russell #644123 - WARR Performance LLC

This is the adapter you need to connect a -6 AN fitting to your LS fuel rail pressure lines (3/8″ SAE quick disconnect). Shipping: These ship free anywhere in the US.

warrperformance.com

And this looks like it would fit the line on the truck.

Earl's Performance AT9894DBHERL Earl's Performance AN to Metric Adapter Fittings | Summit Racing

Free Shipping - Earl's Performance AN to Metric Adapter Fittings with qualifying orders of $109. Shop Fittings and Adapters at Summit Racing.

www.summitracing.com

While I don't have an LS motor, my marine intake uses the same fittings.

Where did u find a marine intake!! I’ve be been looking for awhile. Which is half the reason for the swap. Other is, I’m done with the 4l60. This would be number 3. I figured I could swap everything for the same money to rebuild trans. Having both complete trucks is almost a no brainernow lol.

I got mine off of eBay. . . back in 2012 when you could still find them. If you were to sneak a narrow-pattern cam into that 6.0, you could pick up a lot of torque. I feel ya on the 4L60, the first time mine broke it got dumped for a 4L80.

has anyone figured out to get the 8 lug hubs up front to match the rear? I’m gonna use the 8lug Rearend from the donor truck and would like matching bolt pattern up front.

 

[Supercharged111]

A couple folks have swapped the big diff in and kept 6 lugs, 8 lug front is a chore. I want it too, we have at least one member here who welded in the upper control arm mounts from an 8 lug to bolt that setup in, but the frame itself is taller on those trucks so the only truly correct answer is to frame swap or SAS the thing.

 

[L31MaxExpress]

A couple folks have swapped the big diff in and kept 6 lugs, 8 lug front is a chore. I want it too, we have at least one member here who welded in the upper control arm mounts from an 8 lug to bolt that setup in, but the frame itself is taller on those trucks so the only truly correct answer is to frame swap or SAS the thing.

Are you sure the frame is taller? I was told the same thing on my 97 Express. Had a 1500 and 3500 van frame sitting 10 feet from each other. Same height and the suspension was a bolt-on.. Van uses the same control arms as a truck or SUV. 1500 and 6 lug 2500 has a stamped steel upper and the 8 lug 2500 and 3500 use a forged upper. Knuckles are identical to a 2wd truck save for the tie rod hole is upside down on the vans. The 1500/6lug 2500 vans use the same knuckle and the 8lug 2500/3500s use one with a larger spindle. The front frame section where the control arms bolt on also seem to be identical on my 99 2wd 4-door Tahoe although the engine crossmember is slightly different. All I have done so far is set the caster/camber eccentrics in the middle (I used the OTC tool to push the knock outs out for future adjustment should it be needed) and used a tape measure to set the toe slightly in. It goes straight down the road with no weird bumpsteer, although I need to get it on a computerized alignment machine someday soon.

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[L31MaxExpress]

Where did u find a marine intake!! I’ve be been looking for awhile. Which is half the reason for the swap. Other is, I’m done with the 4l60. This would be number 3. I figured I could swap everything for the same money to rebuild trans. Having both complete trucks is almost a no brainernow lol.

has anyone figured out to get the 8 lug hubs up front to match the rear? I’m gonna use the 8lug Rearend from the donor truck and would like matching bolt pattern up front.

What is wrong with the stock intake? I am running a ported stock intake currently, although I do have a marine intake to port. I am making 412 hp and 430 tq at the wheels through an 85E and 10.5 14-bolt with the ported stock intake and a plenum ported to match an 80mm BBK throttle body.

I swapped a 4L85E behind my old 350 back in like 2013 when the built 65E failed in 40K miles after the stock 60E had failed in 38K miles. I understand your feelings on the POS 700r4/4L60E.

 

[Supercharged111]

Are you sure the frame is taller? I was told the same thing on my 97 Express. Had a 1500 and 3500 van frame sitting 10 feet from each other. Same height and the suspension was a bolt-on.. Van uses the same control arms as a truck or SUV. 1500 and 6 lug 2500 has a stamped steel upper and the 8 lug 2500 and 3500 use a forged upper. Knuckles are identical to a 2wd truck save for the tie rod hole is upside down on the vans. The 1500/6lug 2500 vans use the same knuckle and the 8lug 2500/3500s use one with a larger spindle. The front frame section where the control arms bolt on also seem to be identical on my 99 2wd 4-door Tahoe although the engine crossmember is slightly different. All I have done so far is set the caster/camber eccentrics in the middle (I used the OTC tool to push the knock outs out for future adjustment should it be needed) and used a tape measure to set the toe slightly in. It goes straight down the road with no weird bumpsteer, although I need to get it on a computerized alignment machine someday soon.

You must be registered for see images attach

Just the front bit of frame is taller mostly around the upper control arm area, the rest is the same height albeit thicker. This is for 4wd, I can't speak to 2wd. Someone had a diagram that showed the differences well in another thread a while back. Was an eye opener for me too.

 

[L31MaxExpress]

Just the front bit of frame is taller mostly around the upper control arm area, the rest is the same height albeit thicker. This is for 4wd, I can't speak to 2wd. Someone had a diagram that showed the differences well in another thread a while back. Was an eye opener for me too.

Was that a SRW or DRW truck? My buddies 99 4x4 3500 dually has a taller front frame section but I was under the impression the SRWs were the same 1500-3500. I measured a 2wd 3500 SRW and it was the same as the Tahoe which will be getting 8-lug swapped eventually.

The van frames are the same height and the same thickness everywhere I could physically measure but the vans are fully boxed and hydroformed. The only difference I could find anywhere on the vans was a reinforcement welded under the frame above the rear axle on 8-lug setups.

 

[Supercharged111]

Was that a SRW or DRW truck? My buddies 99 4x4 3500 dually has a taller front frame section but I was under the impression the SRWs were the same 1500-3500. I measured a 2wd 3500 SRW and it was the same as the Tahoe which will be getting 8-lug swapped eventually.

The van frames are the same height and the same thickness everywhere I could physically measure but the vans are fully boxed and hydroformed. The only difference I could find anywhere on the vans was a reinforcement welded under the frame above the rear axle on 8-lug setups.

It's an 8 lug thing since the upper arms, knuckles, and hubs are quite a bit different. SUVs too. 6 lug hubs fasten to the knuckle with 3 bolts, 8 lug uses 4 and the knuckles are quite a bit taller too. Upper arms have a wider span where they attach to the frame and instead of the ears protruding outward from the frame, they stick up off the top. My guess is it was extra beef to hang a plow off of.

 

[stutaeng]

Here's a link that has frame dimensions for the trucks and SUVs:

https://www.gmupfitter.com/wp-content/uploads/2021/07/1999_LD_CKTruckCurrent.pdf