My wife and I had our first child last year, and at that time my wife left her job to stay home and care for our son. In the past I would have just purchased a complete car, but based on current finances this isn't an option. I have always wanted a true project car that didn't have daily driving responsibilities that I could wrench on over time as funds allowed and so hopefully in the next week I will have locked down a 98-02 Camaro Z28/SS rolling chassis. I was hoping to clarify some things prior to that as it will impact what direction I go with my build. The plan is to utilize the local pick and pull for base powertrain and then search craigslist for some go fast parts. So if anyone can answer these questions I would appreciate it:

1. Are there differences between the a 5.3 / LS1 / LQ4 that make a specific wiring harness the preference when building an LQ4? If I can find the harness with the engine I plan on grabbing that and the ECM, should this all connect to the body harness without issue?

2. If the ECM is not available, what ECM would you recommend, what vehicles should I be looking for to grab one?

3. I will need accessories, are there differences between the truck accessories and the LS1 accessories? What would you recommend as a cost effective way to tackle this as finding the accessories from my pick and pull will be impossible as they never have 98-02 LS1 cars.

4. I assume the motor mounts are the same?

5. What would be the best compromise between price and performance for heads / intake? I had planned on sourcing LS3 heads / Intake off craigslist, does that sound right? If I find an 01-04 LQ4 (to avoid the longer crank snout if I decided to use a T56) it should already have aluminum heads, are those good enough? Recommendations on using truck coils or should I source LS1/2/3 coils?

6. Cam recommendations? If this was an LS1 "cam only" car I would be shooting for as close to 400 whp as possible while still streetable, not sure what to expect our of an LQ4 with more cubic inches?

I have no misconception that this is going to be fast or easy, but I really would like to get back into my hobby and would like to share it with my son as he grows up. I appreciate any help/suggestions you can provide.

 

this is just my personal experience so take what you want with a slight bit of caution:
1) I don't believe there's any difference in wiring harnesses between the LS1 and LQ4 and I think the same would apply to the 5.3
2) i'd recommend the 01/02 PCMs. I believe they're the 411
3) there are differences between the truck and car accessories. you'll need the intake manifold, oil pan and pickup tube with the windage tray. the alternator bracket if I recall. regarding the LQ4, make sure its the newer than 02(?) due to th prior LQ4 the crank snout sticks out further which would not bolt up to the trans
4) yes
5) try and get the 243/799 heads. truck coils are a plus but not necessary. if you can get an ls6 intake at the bare minimum
6) are you looking for just horsepower number or 1/4 mile times? that needs to be addressed. my old firebird build was a astraight LQ4 with stock 9.4:1 compression and it ran favorably well with the cam combo and gears and bolt-ons as reference.

 

1) I would try to locate a Fbody ('99-'02) wire harness for the ease of install and mating to the chassis harness. The truck wire harness will require modification of several connectors.
2) Same with the PCM, '99-'02 Fbody,
3) The accessories will depend largely on what intake you plan on using. I am not sure if there are clearance issues with the LS3 intake and the truck water pump. If there is fitment issues, you can buy a specific spacer kit to use an LS1 water pump with the LQ4 accessories and a car intake manifold.
4) I believe the car and truck motor mounts are very different. But you can use the necessary car motor mounts on the truck engine.
5) If you have the budget for LS3 top end, do it, you won't regret the performance for the price. The stock aluminum heads on the LQ4 are pretty good for stock castings though. Any coils really for your application. I've used almost all of the coils without issue. As long as you have the right connections you are good to go.
6) Really depends on whether you go with the stock truck heads (317 castings, cathedral port) or the LS3 heads (square port).

 

I'm mainly looking for a fun street car that I can take to cruise nights each summer in the Chicago suburbs initially. Future goal will be a rear end swap for a 9" and hitting up the track as well. Let's consider this LQ4 build a trial run, down the road I may build a second engine and just swap stuff over so the car doesn't have a lot of downtime. Thanks for the response.

Thanks for the heads up on the harness, I was worried about how it would connect and if it would play nice since the roller will still have the all harnesses other than the engine harness. Any guesses on what a cam only LQ4 on stock 317's would be putting down vs. LS3 heads? Definitely not using truck intake.

 

Now don't quote me on these numbers, just use them as a general guide for what horsepower levels to expect...
With a good exhaust and leaving the LQ4 heads untouched with stock compression you are looking at under 400rwhp going cam-only (exact hp will depend on what intake manifold and exhaust you go with). You could slap on some 243/799 heads to bump up the compression by about a point with the smaller combustion chambers.

Now if you swap to the LS3 top end and choose to bump up the compression (milling heads and/or thinner gasket) you are looking at around 450+ rwhp. Further still, if you get the LS3 heads and intake ported you are looking at close to 500rwhp.

 

Even if those are rough estimates that makes me think they are worth the price, I could probably pick up a set here for somewhere around $600.