Ive spent the last two days trying to search this stuff out and sadly enough i havent had any succes because the search feature hasnt been working.

My project car is 1996 nissan 240sx.

I will be putting an ls style small block in this car.

Here is my problem.
My inlaws own a couple of junkyards so i pretty much have a few choices.
I can have my choice of an 5.3l aluminum block
or 6.0 iron block out of a pick up
or a 6.0 out of an escalade.

Or i can pay 3 grand for an ls1 motor camaro firbird etc.

1.st question is the weight difference from the aluminum block to iron block alot.

2. Do these engines use the same heads or are there different castings of heads between them.

3. Will the gto oil pan and pick up bolt to the iron blocks.

 

Go with the 6.0l block. The weight difference is 100lbs, possibly less. You can build the **** out of them to be 450 NA hp fairly easily or build it better and spray a hp number close to the weight of a stripped 240sx (an exaggeration, but you could spray more than you'd ever need). The heads on the 6.0l are different than the LS1 heads, but most aftermarket cast heads for the LS1 (ETP, TEA TRickflow, AFR. DART) get bolted up to LQ9 based strokers all the time, so you should be fine. Not sure about the oil pan.

 

Before deciding, what are you using the car for? If it is mostly drag only or if ultimate handling isnt a concern, and youre just going after huge power, go with the 6.0 block. If you do any road racing, autoX, etc, that extra 100lbs of iron hanging on the front of your car will be noticable, and the aluminum block LSx engines can handle enough power to make you happy. I would never even consider putting the iron block engine in my RX-7.

 

Well i do everything.

Hpde track days
Autox
drag
etc

I mostly want a really fun all around street car with the ultimate power goal of 450whp.

The engine that is in the car now weights 70 lbs more than a full trim ls1. so thats why i was thinking if its only 100 lbs wont it be more or less the same.
Or would the weight being that much more foward affect it more drasticly.

 

Im not sure the exact distribution on your car, but less weight off of the front wheels is usually a good thing. However if the iron block engine really wont put you much, if any heavier than the factory engine, it may be worth it to you just because of the cost difference between that and an aluminum block LS1.

 

the car as it sits weighs 2680 lbs weight distrubution if i remember correctly was 53.6 46.4 .

Since then it has a carbon fiber hood which takes 24lbs off the front and and a light weight battery in the rear which weighs 7 lbs less. In addition i got the JDM front bumper and ditches the US bumper support in favor of the jdm one which was a weight savings of 17 lbs.

So in all reality ive taken 41 lbs off the front of the car.
and ive moved 8 lbs to the back.