looking to do a 99 lq4 swap in my 88 with the 2.8. I wanna run ls3 heads and intake on it and was wondering what harness and stuff I would need to make it all work. any help would be greatly appreciated

 

Just a heads up, what trans you planning on running. You will have to run an older trans behind that year LQ4 as it has the longer crank.

Anyways. You have a few options. Most buy 99-02 F-body harness and PCM and work off that. I personally just tear the truck harness down and start from scratch but most are afraid of wiring. If you are afraid to wire "pocket" on here sells some plug and play harness.

Obvious other options are stand alone. Megasquirt, Aem yadda yadda.

I plan on running Megasquirt 3x this time around on my build just due to the built in functions and since the mine will be turbo'd. Its around $800 for a prebuilt unit and harnesses

There are a bunch of stickies and info on this board and at LT1swap.com

Jay

 

either a 4l60 or 4l80. my uncle owns a junkyard so I can't get one pretty cheap. I was think stand alone factory harness for now as I don't plan on a super high dollar build. just wanna get some extra power and keep it somewhat simple.

 

You want a 95+ 4l60e with the one piece case or a 2pc version that was behind a SBC

4l80e will work, but that's a lot of trans to cram in the tunnel

To keep it simple, stick a ls1 intake on the 6.0 and call it a day. Stock cam and iron heads still puts out more power than any production 3rd gen ever came with. Plenty of room to upgrade in the future

 

LS3 heads are good, but with their larger chambers than the 317s on the LQ4, and the dished pistons of the LQ4, compression will suffer. I'd go with Pocket's advice there. Well, actually I'd go beyond that and suggest pulling the heads, shaving them to 65cc, upgrading the valve springs, and putting them back on the LQ4.

Should you rebuild it in the future, flat top pistons would play nicer with the LS3 heads.

In the "while you've got it apart" department, a cam upgrade would also be nice. Since you've already increased compression and upgraded the valve springs...

Or, like Pocket also said, the LQ4 in stock condition will have more power than any 3rd gen from the factory. And about 2.4 times what your 2.8 had.

 

would a ls2 or ls6 be better than the ls1 intake?

 

Yes at an extra cost. If you're going that route go with an aftermarket aluminum intake, bbk, weiand, typhoon etc. Cost is comparable with aftermarket flowing more. Deep pockets go for a fast

 

had no intention of buying a new one. been watching eBay a lot and Craigslist and was wondering if it wouldn't be any extra work to run the ls6 manifold

 

I would go ls6 intake over ls1 any day. And I agree..to keep it simple do a cam swap and valve springs/hardened pushrods with the ls6 intake. All else stock with my 6spd and 3.23 gear I layed down 310whp/330tq.I jumped significantly in power by only switching to 243 shaved heads..and furthermore going with longtube headers.Doesnt take much to make steam with little invested.