Confused on Lq4 to obs conversion.

[Pavetim]

I read the sticky and it talks about custom harnesses and stuff. but what I'm wanting to do to my 98 c1500 4.3L. Is take a lq4 from a 2004 van with cable tb. I'm going to get a ecm and harness out of it too. I want to run a 4l65e. What all do I need to do. I know about the frame and mounts i'm mainly concerned with will the harness and ecm work on my truck?

[keniff]

the harness will work..the problem is youll have to get the gas pedal, the tac module (i think thats what its called) IMHO get the motor/tranny ann brackets an bolts the ECM, an try an talk them into giving you a harness from a 99-02 truck. rework it yourself or send it to Jon @ Nelson Performance, or you can spend 650 for Jon to make you an AWSOME cutsom harness.
all you need from your factory harness is you ALT wire, starter wires, water temp, an oil pressure. youll need to keep the fuel wiring under the hood also. sort out your windshield wiper harness also.

go with a 99-04 radiator (28") an add e-fans from a 99-02 camaro/firebird, or add the 05+ 32" radiator an e-fans with a Nelson Performance harness.

i got my adapter plates from Josh Powers for a good price imo. they're 3/8" plate vs 5/16..just a thought.
go look in my build thread in this section an you'll see a parts list an almost a step by step write up of stuff.

good luck

[Hardrock]

Keniff, IIRC, I think the '04 vans were DBC not DBW. A better route to go IMO.
Less wiring and less problems, cheaper to repair down the road.

Pavetim,
From what I've gathered here and on other LS1 boards, the 4L60e/65e
probably isn't a good match for a 6.0 unless you plan on leaving it stock.
A moderately modded 6.0 will really tax a '60e and a heavily modded 6.0
will shred one pretty quick. GM put the 4L80e behind the 6.0 for a reason.
Save yourself the grief of re-programing the van ECM to run the 4L65e and
changing it back again when the '65e bites the dust.
Best to go 4L80e from the start.
The van ECM and harness should already support the '80e as is.

On another note, I've often thought the OBDll trucks (your 98) would be
easier to swap than the OBDl's, as alot of your truck's already setup to run
through the ECM to begin with. (VSS, cruise, TCC, ect.)
Somebody correct me if I'm wrong.........I'm new here!

[LS1GMCTruck]

If your going with a cable throttlebody, you don't need to get the foot peddle, etc... Just have the computer programmed as a stand-alone system, wire the power wires to the computer, and fire it up. I take it your using the same tranny on the engine that it came with, out of the van? If so, your good to go, computer & harness wise. Your existing throttle cable in your '98, will snap right onto your new engine throttle-body. Note to self: hang on to your trucks original tranny, until your swap is 100% complete. I did'nt, and had to scrounge all the small parts that I needed from my old tranny. Things like the nuetral safety switch, bolts, cable bracket, longer shift-shaft, etc...lol

[Pavetim]

Ok cool thanks guys. I'll probably go with the 80. Everybody doesn't seem to feel the 60 or 65 will hold up. I'd prefer the 65 for the gear ratios though. I'm only doing exhaust and tune on this, i'm not planning on modding it too much. But since it is dbc i'll try to find an ecm and harness out of a express van so it will pretty much be plug and play.