want to put ls1 or ls2 into 88 c1500

[LS1GMCTruck]

No. The LS harness you get, should be the correct harness, that goes with your LS engine & trans that you choose. You don't have to cut off anything. Just sent the harness(& puter) to someone like Nelson Performance(the sponsor of this board), or Wait4Me Performance, etc., and they will send it back to you ready to snap on your engine. There will only be about 4 wires to hook up(some keyed power, some full-time power) to the wires already under your hood, and it will start right up & run. They will provide you with a couple more wires that you hook to your exsisting gauge wires that come out of your dash on the drivers side. Your older truck has analog gauges, nothing thats digital. Your oil pressure & temp, & fuel level, & speedo gauge, etc., wires need to be identified(by color & location) as they come through the firewall, just below your brake booster. Hook those together & presto!...the gauges work, lol. The harness ends will all be labeled when you get it back.

[marofever]

ok that just about clears it up. i knew it would be the correct harness, just wondered how my guages were going to work and why exactly it still need to be modified but that makes sense..modify for the guages. im just glad i have the best of both worlds, a great looking simple obs without all the electrical itnerferance of its newer but same bodystyle counterparts so i can get it done so much easier. i do think im leaning towards going sixspeed though. i can only imagine how much fun that will be lol.

thank you for your clarifications LS1GMCTruck.

[Chevy-Art]

There will only be about 4 wires to hook up(some keyed power, some full-time power) to the wires already under your hood, and it will start right up & run. Your oil pressure & temp, & fuel level, & speedo gauge, etc., wires need to be identified(by color & location) as they come through the firewall, just below your brake booster. Hook those together & presto!...the gauges work, lol. The harness ends will all be labeled when you get it back.

What he said. Have you removed your engine? If not, find the water temp sensor wire located on the left side, it is between plugs 1 & 3 and label it. Also the oil sending unit located at the back of the block, label the wire going to it. The speedo is two wires purple and yellow they are under the master cylinder, those two go to the pcm. Gas and voltage I didn't do anything with them, but they work.

[marofever]

cool. i bet i can figure it out. thanks, i just like to make sure fore i go cuttin stuff up. lol. i took a look at your build chev art. nice. ima noob here so i havnt filled out my pro yet or posted any pics of my truck yet. my truck is exactly like yours but a stepside. im still in the planning stages, actually more of its planned.....just have to discover an acceptable candidate. plus im still kinda wondering how far she will go. lol its got to have around 300,000 miles give or take, the odometer reads 196,700 but i found paperwork for tires in the glovebox when i got it two yrs ago and the mileage on the paper is the same, that was in 2001 hahah. im the 4th owner, the previous owner was my father n law and the owners before that used it as a shop truck. amazingly it was not all beat up or scratched up like a typicalwork/shop truck. its very clean for an 88. its never been rebuilt or messed with other than me unclogging the oil return holes in the heads and it still has about 50psi oil pressure and purrs. im still afraid of it though hahah, even though ive never had an issue with i still expect the day shell let me down.

thanks guysfor your help and if i have more ?'s i know where to go.