wagner262

So I have a few questions about a future build.

My goal is to build an lsx tt from the block up. Then drop it into a classic muscle car either chevelle or gto 67. I am going to start with just the block for now and make it a long term project.

My question is I'm leaning towards an ls2 build since I don't really need 1000hp+. 600-700hp is what I think is good for me. That's why I landed on the ls2 and not an ls3 or lq9 iron. I'm not looking to race it much. Maybe a track day or two just for kicks. Does an ls2 sound about right or should I just got for the ls3 ls7 or lq9?

Next question is what Is the best way to go about this? Buy a new block? Buy a used engine? Buy just the used block? Buy a wrecked car and pull the engine? I don't think I would use many of the stock parts. Plus if I did need parts the lsx are always for sale. Looking to save money and not over spend for parts I don't need.

What do you guys think? Any suggestion would be appreciated!

old motorhead

The bottom dollar cheapest route would be to use a 5.3L truck motor as the starting point. Plenty of size to hit your numbers with mild boost. Start with a low mile take out and I wouldn't even bother building it. Add a cam and maybe a set of 243 cylinder heads along with the power adder of your choice. Those 5.3L's are tough as nails too.

A notch up from there would be to find an L33. That's an aluminum block 5.3L with 10:1 compression and has LS2 heads already installed. I'd look for one of those out of a wreck that has all of the accessories along with PCM. Might even be able to swing a deal to get the tranny along with the motor. That takes a whole lot of the work out of putting a newer engine into an older car. One donor.

Those iron block 5.3's are cheap and easy to source. If you pop one, $600 will buy you another. L33's are a little more expensive and harder to find. 6.0L LQ4's are more expensive than iron block 5.3's, but usually cheaper than L33's.

Use your wallet to guide you. Any of those options are capable of making the power. Built LS7 would be the sexiest and most expensive. It all ratchets down from there

wagner262

So I'm leaning towards the lq4. I want to rebuild the engine from the ground up for reliability and learning experience. With the lq4 I can run a manual tranny like the t56 correct?

old motorhead

I don't see why not. I have a T56 I'm planning to put behind a supercharged LQ4. An LQ9 is also a 6.0L iron block that you sometimes run across in the boneyards. Higher compression ratio along with supposedly LS2 style connecting rods. Usually more money though. If you're going to rebuild it anyway, maybe not something to consider.

schpenxel

Some guys on ls1tech are making stupid power on those truck engines.. Not sure if it's the exact same one, but I can only assume it is. I saw an article where they took one, opened up the piston ring gaps some, slapped a turbo kit on it on the dyno and made over 1000rwhp and never could get anything to break after like 50+ pulls

I'm sure real world driving would be harder on it than some dyno pulls, but the point being they are quite strong for the price..

Hard to beat that, unless you're paying for labor

old motorhead

Yeah, and one of those huge hp motors turned out to be a 4.8L truck motor instead of the 5.3L. 4.8L is just a destroked 5.3L. The 5.3 has the same stroke as an LS1,2,3,6 at 3.622. The 4.8L uses the 5.3 bore with a 3.27" stroke.

schpenxel

Even better. Yeah I think I saw that one.. Pretty crazy. I have to laugh at some old LS build articles that advised stronger internals were needed if you were going over like 500hp, lol.

wagner262

Awesome thanks guys looks like I've made a decision for the lq4! So if I'm looking at putting it into an old school I'd obviously need a different wiring harness but I there any other accessories I would have to swap?

There are multiple junk yards where I'm at I might just pick one up from there

wagner262

So the cheapest engine I could find was 1300 or so with everything but tranny. Im wondering though if I should buy a block for 400-600 since I will be replacing many of the internals any how. or would it be worth it to get the entire engine and sell what parts I dont need and use the accessories?

schpenxel

How much for just the block? And new or used?

Personally I'd rather start with something that is all together, but I guess it depends on how much you plan on doing to it

old motorhead

Get the whole thing with all the wiring harnesses you can snag. The accessories can drive you batty getting all the brackets, hoses, harnesses, etc. Also, I think 2004 and up have e-fans vs crank driven cooling fans on the earlier models. Lots of flexibility if you have the wiring and pcm that will play nice with the e-fans. In a truck, you can damn near stand between the motor and the radiator if you're using the e-fans.

wagner262

I cant find anything about the fan but im wondering if I could swap it in if need be? The engine I found for cheap was an 01. I heard I should stay away from the 99 and below

old motorhead

I think the crankshaft is different on the backend of those early 6.0's. Seems like some of the earlier ones had iron heads too. Pretty sure you'll have a crank driven fan in '01 and also probably a cable controlled throttle body. Allen Nelson, of Nelson Performance in San Antonio, used to make a wiring harness to convert to e-fans on those early LS style truck motors.

wagner262

Yeah they have iron heads but didn't bother me since I'd be buying different ones anyhow.

old motorhead

I think iron heads ended after model year 2000. You might make sure of your crankshaft too. Not sure, but it seems like I remember the mounting flange on the back of the crankshaft being thicker on the earlier LQ4 motors. They took different flywheels/converters.