I made this writeup for another site after some guys were asking me questions and I figured it might do some new swappers some good on here:
Alright, I had a handful of guys wanting more info on how to swap in an LS-series of engine on a limited budget. I do these conversions for a living and will try and help shed some light on installing one of these in about anything on the lowest budget possible. Dependability, great power output, mileage and the cool factor all can come at a very reasonable price if you are willing to work a little for it.
First off a little about the engines I will be referring to. In my world I refer to either the 4.8, 5.3, 5.7 or 6.0 engines as LS1 as they share the same platform and most parts with the actual 5.7 aluminum RPO LS1 engines. I rarely do ACTUAL LS1 swaps and here is why. The two main advantages a Camaro/ Firebird/ Corvette LS1 have over a truck 5.3 for example are that the aluminum block weighs 65lbs less and they usually make around 10 horsepower more. These two factors do not warrant the big difference in price to me. There have been dyno tests were 5.3s were swapped in place of 5.7s and with all parts the same (intake, etc) they usually made 9-10 horsepower less. This is obviously NOT a large difference. I'm not bashing a true LS1 by any means, but the 5.3s can usually be bought for 1/3 to 1/4 of the price, so I tend to use them.
With some digging around, you can usually pickup a complete 5.3 for anywhere between $450-$750. The way I usually get them is top to bottom, with truck intake/ rails/ injectors/ coils. They usually do NOT have starters, alternators, power steering, etc. This is just the way I get them. I have bought 18 of them this way.
The next biggest expense is usually the harness, which you have different options. Either harness can be made to work, be it from a truck or a LS-car harness (Camaro, Firebird) The biggest differences are that the trucks use a different injector plug type than the cars and the truck harnesses lay out differently. I try to avoid the truck harnesses as much as possible due to the odd layout, they are harder to make look nice and they are wired a little more complexly than the car ones (more keyed power sources) Here is where you have to decide what direction you are going to go, plan on leaving the less attractive truck intake (still make good power) or switch to the car style intake/ rails/ injectors to make it look more like an actual LS1. A stock harness usually will run around $150-200 dollars and you will then have to spend 3-4 hours cutting it apart/ figuring out the wires that won't be needed for your application and removing them and finding the wires you will need to connect to make your swap run. This is not a very difficult task, but it does require some patience and a good source of info, such as: http://www.ls1tech.com/forums/conver...swap-faqs.html
This would be the cheaper route to go if you are somewhat confident in wiring, the other route would be to buy an aftermarket or already converted harness. I have previously reconfigured all factory harnesses for my swaps but now we sell our own, all new harnesses for less than a stock harness and the labor required to modify one. These start around $500. These are made with the correct length wires to place the ECM better and layout more pleasing to the eyes. It would take a lot of work to modify every wire on an older harness to make it layout as nicely as one of the custom built from scratch harnesses.
The next item to consider is what transmission you plan on running. The LS engines will work with any older GM trans with some considerations. TH350s/ 700R4s/ TH400s work by using a GM part as a flexplate spacer and bolts to place the flexplate at the proper spacing, and this part provides a place for the converter snout to engage, using the original converter. The thing to consider is the downshift/ TV cables associated need to be addressed. Companies like Bowtie overdrives, etc have pieces to make them work. Obviously the 6-speeds/ 4l60Es designed to be behind the LS-engines work easily with the proper harnesses if your budget allows.
Next would be the fuel system. The easiest way to do this would be to use an inline Walbro pump sold all over the net, usually around $120 and the corvette filter-regulator combo. There are many options here depending on yor vehicle as far as getting the fuel to the pump. You can pull your factory sending unit and find a way to mount the pump to the sender and install in tank, or maybe even an aftermarket vendor makes a sending unit for your application to do just that. Other options including welding a sump to the bottom of the tank and feeding from there. Next would be installing a fuel cell or even an aftermarket tank designed for EFI use in your application. Some even just mount the pump and pull fuel through the factory pickup. This is usually okay for lower horsepower (stock swaps) and certain pumps, as some don't like pulling fuel very much and might not last forever. After the pump, you feed the corvette filter/ regulator which then has an output that you run to the fuel rail and it also has an output for return fuel back to the tank which just needs plumbed into the top of the tank. The truck intake and fuel rails includes a regulator so you can just run a line up to it and a line back from it returning unused fuel to the tank.
The only other variable here is what accessories you need to run on your engine. Of course there are vendors out there like March, Kwik Performance etc that sell complete accessories setups that are nice, but pricey, which doesn't fit into this budget writeup. I usually am doing hotrod style swaps that often only include an alternator. These are fairly simple, I usually use GM CS-style alternators, found in TBI/ TPI style 4.3-5.0-5.7 engines. These are pretty affordable, work well and are easily replaceable in case of failure. Making mounts out of simple metal (3/16s bar stock-3/8ths round stock) doesn't take too much skill. Just mount the alternator out of everythings way in your swap and most times you can even route the belt to use the factory tensioner. I have done many this way and even some with power steering and used the factory tensioner with perfect results. None ever took more than two hours to figure out. For the non creative types the easiest way to do this is to hold a straightedge across the balancer and hold the alternator up to it in a good spot and find a way to tack a bracket in place to hold it temporarily and then build some easy brackets (I love using the round bar) to mount it, it doesnt even need to adjust if you use the factory tensioner. Of course using factory LS1 brackets/ accessories is always a possibility if they fit your application and are available for use. The thing to keep in mind is that the truck/F-body/Corvette all use different accessory spacing in regards to the distance from the pulley to the block, the trucks stick out the furthest, the F-body is in about 5/8 from that and the vette is in a little more. The total difference between all three is around an inch I believe, but it is enough to make obvious bracket issues if trying to mix and match parts.
Well if you are still with me I am going to make a few lists with pricing for a few different situations.
First would be low budget, this would include a 5.3 engine swap, leaving the truck intake and using for this example a TH400 trans that was already in the vehicle.
5.3 Engine $450
Stock truck harness $150
Add on fuse panel for harness $40
Conversion mounts $50
Gm Trans adapter/ bolts $50
New starter $80
GM CS alternator-junkyard $25
walbro fuel pump $120
Maf sensor - used -ebay $40
New O2 sensors $120
radiator hoses $20
Fuel lines/ fittings $100
Computer reflash $150
Exhaust work/ O2 bungs $100
This would be the bare minimum swap into a vehicle. For example I just did a swap like this into a 69 Chevy truck. This has no hood clearance issues for the taller intake, standard truck manifolds that came with the engine fit the chassis in this application. The trucks stock radiator worked excellent as the LS-engines run pretty cool anyhow. The truck had existing electric fans like many vehicles out there already may have.
This swap would have been for the more do-it-yourself kinda guy as it used a stock harness requiring the modifications to make it work.
Now, take that same swap and add the car intake/ rails/ injectors and use an aftermarket harness which is already done, wires in with only a few connections and looks much nicer.
Previous price $1435
LS1 intake $80
LS1 rails $50
LS1 injectors $40
aftermarket harness (ebay) $500
credit back -truck harness -$150
credit back - fuse panel -$40