5.3? or 6.0?

[t72ss402]

I am at a toss up from using the a 5.3 or 6.0.

The car is going to be a driver (not daily but driven a little more than on the weekends) all factory accessories such as a/c, power steering, and power brakes.

First how upgradeable is the 5.3s? Like maybe factory LS1 heads and intake, and GM hot cam kit. Will this combination be possible and what kind of power would this combination produce?

With this set up would you need to run the f-body computer, and harness with the LS1 intake?

Same combination for the 6.0. But want to look at using 4l60E trans for ease of installation.

The computer, would any computer work? If I am thinking right all you need to do is reprogram it with your set up and upgrades.

The 6.0 would be great but 5.3s are so easier to find.

[matty b]

I bought a 2006 lm7 (5.3) with 15000 miles for $800. They use the same crank and rods as all the other gen3's excluding the 4.8 and 6.0 so they are just as upgradeable as any of them. I dont recommend swapping to ls1 heads since the chambers are bigger and they severly drop compression, same goes for ls6 heads. The heads flow almost as good as ls1 heads but have smaller chambers for the smaller bore size. I already installed a 2002 LS6 cam and valvesprings along with ARP rod bolts and headstuds. I am tossed up whether to use the LS6 intake or get the Professional Products Typhoon Intake although I think Im gonna go with the Typhoon due to cost and the claim that it bumps power over the LS6. All in all the 5.3 is just a small bore LS1 with a cast iron block and thats about it. All parts for a Gen 3 will bolt up to it though so anything goes. You can also have the block bored out and run LS1 pistons and have a cast iron LS1. If you port the heads and keep the chabers the stock size you get a nice bump in compression and alot of LS1 guys actually use the heads for just that reason. Im planning on turbocharging and I like the added strength of a cast block. You can use the stock PCM and harness on the LS1 intake however you need to splice on injector connectors for the ls1 injectors and checge the Injector Flow Rate in programming to compensate for the bigger injectors (this is very easy so dont think that its some crazy modification). The truck harness also drapes over the drivers side valve cover and looks hideous so I would recommend the F body harness. If you do use the F body harness it is necessary to just do the IFR programming. The pinouts are the same for all of the motors at the PCM however the LS1 has electric fan out puts built in and if you use the truck computer you need to turn on the fan outputs in programming. I dont recommend using the LS1 computer though since it it tuned completely different. As a side note, if you do run the car intake, it is necessary to change the front drive and water pump to match. If you want to run the truck intake manifold you may have hood clearence issues and it looks hideous so just plan on running F body front accesories. This includes the balancer, water pump and accesory brackets. I dont know what car this is going in but you will need a modified f body oil pan or an aftermarket one such as the Autokraft pan or the Moroso pan. With the cam upgrade you should be equal to the 6.0 in hp. The LQ4 or LQ9 requires the same amount of work to the engine so there is no benefit choosing one over the other in that dept. The 6.0 is quite a bit higher priced but it come with advantages that you can get with the 5.3. With the 6.0 you can run the L92 heads which are fairly similar to the LS7 heads and are the hot setup right now. If you go that route you gotta run the LS7 intake manifold to match up to it. The 6.0 offers more hp in stock form as well so its a trade off one way or the other. I decided to save money on the price of the motor cause I will make it back up with a pair of turbos on it but if you plan on NA power then the obvious choice is the 6.0 if you wanna make over 400 hp. You say that you are gonna run AC and I want to let you know that unfortunately the AC compressors that come on the motors arent compatible with Vintage Air setups so figure that into the cost. Whichever motor you plan on buying follow these step to save the most money in the process and with the least amount of parts left over.

1. Get the motor without the front drive. If they offer a price reduction getting it without the stuff on it you are already ahead of the game.
2. Get the motor without the intake manifold or wiring harness.
3. Get an F body balancer, front drive, water pump and wiring harness.
4. get a car style intake manifold. The LS6 is the only stock intake manifold worth paying for.
5. Get the truck PCM
6. To save time and headaches get an LS1 conversion kit for your car including oil pan and modified pickup, motor mount adapters, trans crossmember if you have an F body car this is going in and headers.

All that should get the hardware taken care of. You may need a new driveshaft, efi fuel system conversion, radiator, harness modification and engine reprogramming. If you need help with the harness or reprogramming the PCM shoot me a PM and I can help you out.
Hope I was able to cover as many questions and answers as possible

[trapin]

Matty has some great advice. If I can add to it I would say that you could probably bore that cast iron block to a 4" bore. From there I'm guessing you could then use the L92 heads on it and go with the L76 intake conversion kit through GM Perfomance. Lots of potential in that 5.3. I have one in my 2002 Silverado and I think for what it is, it's the most powerful engine I've ever had in any truck. Like Matty said, you could probaby just do some work to the heads, stick in a mild camshaft (220/222) and an LS6 intake and for a driver I think you'd be pretty satisfied.

The L76 conversion Kit is $556.19 for the intake, TB, fuel rails, and injectors.

http://www.sdparts.com/product/12590...L76L92Car.aspx

Also...here is a previous thread that talked about modifying the 5.3 liter.

https://www.pro-touring.com/forum/showthread.php?t=26531&highlight=5.3

[matty b]

I dont believe that you can safely bore out the 5.3 to a 4" bore. I could be wrong but to the best of my knowledge the walls get too this on that casting. Might wanna double check on that but I swear I remeber being told not to do that. As far as heads go check out Patriot Performance, they have killer CNC 5.3 heads and they are like $900 without a core. There are many avenues for bolt on performance for the 5.3. Turbos, blowers and heads and cams. You never said how much horsepower you were looking to make though so what youd need to do are diverse depending on your goals.

[t72ss402]

I am looking to get 400 horse which i do beleave is very possible with the 5.3, There is no question about the 6.0. I am also looking to do this swap on the cheap, but not cutting any corners. Something like GM would have put in from the factory.