Ok, so I'm planning on doing an lq4 swap in my 70 nova from a 2004 gmc 3/4 ton. What I need help on is the wiring harness and heads. I was wondering what you would do with the heads? I was looking at the l92 heads from gm and they seem like a really good deal at 800 bucks, but would I be better off just porting the stock heads? I'm just looking to get around 500hp with head cam and intake swap. My second question was if I should use the truck harness buy a new harness or use an ls1 harness from a z28 camaro? I'm trying to stay on somewhat of a budget (broke college student)and was told it would be at least 1000 bucks to take the old truck harness out and make it work for my car (I really dont do wiring and dont want to burn my car down with my crappy wiring job) planning on running a 4l80e so would an ls1 harness even work for that? Any help would be appreciated!

 

If money is a problem just run the stock heads or pick up a set of 243 heads in the classifieds. As for the harness you can use a truck one its just more bulky. You should be able to piece together a wiring harness setup for less than a grand

 

You also need an LS3 or L92 intake for the L92 heads. So figure that in. As well as a 90nn DBC aftermarket TB if you want a cable one.

If money is an issue I would run the motor as is get it swapped in and get it running then worry about mods later as head swaps are easy.

 

It would cost about 35 bucks to do the harness yourself. That is tape wire cutters, strippers, a small fuse box and butt connectors from oriley. You really don't "wire" anything, except a couple or relays and a switch to turn it all on.... more swapping removing and re-pinning than anything else. you can do this easily with the pin outs from alldata. if you would like i could get you those for you.

 

This site will help you do the harness yourself.
http://www.lt1swap.com/
As for heads, etc. Just get the engine in the car, then see if you want more power. I was going to do the L92 heads on my LQ9, but found it was fine stock in my 68 vette.

 

Thanks for all the info! after reading up on the harness' on lt1swap I actually think I might be up to putting the harness in myself. I was thinking of maybe just doing the cam for now while the motor is out of the truck, what cam would you guys put in it for now? I'm not going to put any power adders on it since I don't want to have a rollcage.

 

Shaving your heads and a new cam should be all you need....well, that and some new gaskets.

 

If you're on a budget, keep in mind anything more than an LS6 cam will probably require a custom tune.

 

Yeah one of my buddies has the programmer thing, he said it will be like 200 bucks to tune it

 

Also,

If you are going to go with L92 heads, as stated above you will need an LS3 intake which will require different connectors for the injectors and possibly the MAP sensor, depending on the year of the LS3 intake.

Jon
PSI

 

If you do your harness yourself; use heat shrink and solder on spliced wires etc., it looks better and IMHO seems stronger than butt connectors. You can get it at any parts store and all you need is a lighter for shrinking. Harbor Freight has an assortment box of it for 3-4 bucks.

If your on a budget that seems the way to go. I wouldn't go to radical with the cam; as stated above ls6 would be a good choice. I know you probably don't like the ugly truck intake but if you search this site there have been a few people who have cut the plastic pegs off sanded and painted their intakes, and they look pretty good compared to stock!

I wouldn't go ls3 on heads; your on a budget and to go that route you'd have to buy different intake and injector harness. As stated above look for some 243 or 799 heads, but honestly the 317's aren't to bad, just lower compression.

Good luck!

 

Actually, the LS3 injectors have the same truck style EV6 connectors and should hook up with no adapters needed and plug right up to a truck harness. Vs. EV1's of the LS1/6.


Also, one will need a electronic adapter box for the LS3 DBW 90mm TB to the earlier truck DBW TB. The truck Gen III MAP can be made to work in the LS3 intake with the correct Oring as the holes are different sizes.

 

I am in a similar situation as you, I have a 70' Nova and a 2003 LQ4. I opted to go with LS3 style heads and intake, but it is really not budget or time friendly. I actually startied picking through my truck harness last week, it really is not that difficult once you get your bearings. If I were in your situation I would run the stock 317 heads, a mild cam, rewire your own harness. You can always add the LS3 heads and intake later if you feel you need more power.

 

IF you cut .030 off the heads, you new compression will be approx. 9.8-10:1

Here are the factory specs on an LQ4 (but lost who posted and can't give credit) :

4.000" bore
3.622" stroke
6.098" rod length
1.338" comp. ht. pin location
-6.7cc dish piston
71.06cc chamber
0.051" gasket thickness 4.010" bore
9.24" block deck height

 

Yeah the truck intake is super ugly but I did look at some pics of it painted and it doesnt look half bad. I think I'm just going to keep the heads and intake that are on it for now and paint it. Also, if I buy the ls6 cam do I need to buy new springs, lifters, etc. for it or am I ok with the stock stuff for now? Again thanks for all the help!

 

You at least need new springs with that cam.. If you do lifters you have to take heads off so if you do that then do swap to 243's.

Youc could als do a TBSS/Gen IV 5.3L intake swap. Its 87mm intake and TB. Then you would still need a TB adapter box for the 87/90mm Gen IV TB to Gen II harness. You can get the X-link form torquerush.com couple hundred bones but you get a better flowing and larger intake than the regular truck 78mm unit.

 

couple shots of my 03 lq4/4l80e combo in my 71 velle.... TR cam, 8.1 injectors,3200 yank converter...made 391rwhp last fall....
Rick

 

Hey looks nice rick! I have about that much hp at the flywheel now! Have you run it to the track yet?

 

The truck injectors will be the same if it is a flex fuel engine. If they are not flex fuel, the truck harness will have multec injectors.

Jon
PSI

 

Is 500 horse with l92 heads, cam and intake on a lq4 a realistic goal? I don't see you achieving that goal. Maybe on a boosted set up...