buffalohd

Well I am new to the world of the LS. I am building a street rod. decided to go with a 5.3 truck engine. The only reason for going with this is the cost and have good things about building them. I purchased a 2003 out of a med duty truck. I would like to get the most out of my build. First I have heard that a LS6 cam wakes it right up? I have good and bad things about using the stock heads? The main thing is I would like to run a GM performance ECM and harness that will work well with a 4l65e. In order to run the new ECM I need to put a 58x crank. Will a late model crank bolt into a early block ( same size journals)? Any help would be appreciated.

Tan327

iTrader: (15)

Why not just stick with the stock PCM? Stock 5.3 heads are okay but there are better options. The LS6 cam is definitely an improvement over stock, but again there are much better options out there. All depends on what yours goals are. I know you said you want to get the most out of your build but not really sure in what area you mean. Is this going in a street cruiser, street/strip car, or track car? Just need to know your goals & budget and we can probably tell you anything you need to know.

Edit: Sorry guess I should have paid more attention, I see you said street rod. What is your budget for engine mods alone and how much do you care about drivability? Are you willing to sacrifice some for performance or are you looking for a happy medium?

buffalohd

I have a budget of about 5k. I would like to have 430-450hp out of it. The engine has over 100k on it so I know that it is going to need to bored. I would like to upgrade to fly by wire. That is why I want to go with the GM performance ECM. The other thing with a stock ECM is it is going to look for other inputs and start setting codes. Plus the Performance ECM will communicate well with the trans controller. From what I have read to make the performance ECM work it needs a 58x crank.

Tan327

iTrader: (15)

The engine may not need work, a lot of people tear these things down with 100k+ plus miles and they look new. 430-450 at the crank may be possible, not likely at all if even possible to hit that at the wheels through an auto without a power adder. I'd talk to one of the sponsors about a custom spec'd cam for your applicated, I like Geoff @ Engine Power Systems but have heard great things about Martin @ Tick Performance & Brian Tooley Racing as well. As for heads you can stick with 5.3's and pick up something like TSP Stage 2 5.3's for around $1,200, or send yours off to Advanced Inductions which make great numbers but are a bit more expensive. 243 heads are an option as well, but will drop compression so you'd want to mill to make up for it.

Any reason you want to go with drive by wire? There really isn't a benefit and honestly the "throttle response lag" is a bit annoying if you've driven a vehicle with one, it may technically be as responsive as a throttle cable, but it definitely doesn't have the same feel.

No offense man but I think you should do a little research in the Hybrids(https://ls1tech.com/forums/conversions-hybrids-28/) section, it sounds like you are trying to make this a lot more difficult(and expensive) than it really is, using this "GM performance ECM", like you said you're still new so there is a lot to learn, nothing wrong with that. People run the stock PCM and build a harness for these swaps every day, I've never even heard of this ECM you speak of. The stock PCM controls the trans as well, so no need for seperate ECM's and TCM's. As for it throwing codes, not an issue, once you have it tuned to disable VATS the tuner can also disable the codes and stop them from returning.

buffalohd

Thanks for the quick response. I have 2 vehicles that have drive by wire my Ram pickup and my Harley. I work for one of the big three. I am looking for performance and fuel economy. But anything will be better then what I was running 57' 283, 350+ hp 4spd and 4.88 gears.

Tan327

iTrader: (15)

No problem, I've had a few rides with DBW and didn't mind it, but I definitely would not spend any extra money to switch to it.

Bilster

iTrader: (21)

There are sponsors within this website that sell harnesses with ECMs tuned to your needs. This is commonly called a "mail order tune". You give them all the parameters. They remove vats and any other feature within the ECM that you don't need and manipulate fuel and spark curves based on your input....all for less than $800! The sponsors that I know have fantastic tech support and will walk you through any problem you might have with your installation. Pick one and have a conversation with them. There is a formula for your horsepower goals that others already have found and are willing to share. Like Tan327 says, you're making this a lot harder than it is. Your not blazing any trails that haven't already been well traveled.