Not that I need one right now, but I'm considering building a new engine for my Y2K. I missed out on buying a new LS1 or LS2 aluminum block (maybe someone somewhere has some warehoused, but regular searches have yielded no returns) and I'm considering buying a new, iron GEN III 6.0L block (they are almost gone too) along with a 4.0" stroker kit to make a 402. I know there are conversion boxes/harnesses for the Gen IV (LS3, LS7) stuff, but I figure if I build a Gen III block I can keep the cam and knock sensors in the same place, minimizing any potential issues with adapters. The iron block weighs about 100lbs more than the current LS1 block and I hear folks talk about it messing up handling and other front-end issues. Has anyone actually installed an iron-block engine in their C5 and noticed negative effects? Heck, it's a little more sprung weight and I can just lose some weight myself and balance out some of that .

I know installing a stroker is going down a rabbit hole of new clutch, upgraded six speed, torque tube and rear but those parts are apparently weaker on the early C5s and I think my belleville washers are going (gone?) anyway...so rebuilding the rear end with C6 parts is in the near future anyway. I don't plan on drag racing much but would like to get more into autocross and maybe a little spirited street driving sometimes. I've built quite a few small/big blocks in my time and have all the tools needed for the build.

My main question is if anyone has really noticed having an iron block vs aluminum up front. Thoughts?

 

I had that exact engine in my previous '00 FRC. Current car has an LS2. so pretty direct comparison. The current car feels slightly lighter in front. so slight it may be my imagination. I thought the weight difference was more like 70-80lbs? You could get a light battery & relocate it to the back, that would take care of half the weight difference.
I would not worry about the weight at all. The previous car drove extremely well, I did plenty of spirited street driving in it and 100% enjoyed it. The guys I sold it to got pretty serious about track events and that iron-block car was/is very competitive even in tight auto-x courses with real fast weight transfer. They did relocate the battery and also added a lot of coolers & such which added weight as well.

 

Thanks for the personal perspective. I can't imagine the extra weight of the iron block would make that much difference, especially for street driving.

 

You could also try looking for a 5.3L L33. It’s a gen 3 aluminum block, can be bored to ls1 spec or if you’re feeling spendy resleeved for big cubes

edit: I think the 5.3L LM4 is also a gen 3 aluminum block

 

Why not just modify your existing LS1? The only real reason to switch to iron block is if you're going BIG power. From your intended use, it doesn't sound like those are your goals. You can easily put 600+ HP on the stock LS1 block without any issues.

 

I note that GM is selling a 6.0 iron block crate engine (LS364) as a direct replacement for the LS1, with the proper reluctor. Currently $4,909.

 

That has L92/LS3 style heads, so you would need LS3 intake at least, possibly adapters/harness extensions if components for those heads are different or in other locations, also a new tune.

But yes it could be a good replacement engine.

For $4999.00 you can get the LS3 long block engine in stock form that’s rated for 430-436 hp in C6 vetted depending on exhaust bypass.

Of course with this engine you need LS3 intake and same things mentioned above plus a Lingenfelter converter box to convert 58 tooth to 24 tooth.

For more $ they offer LS3 long block with GM hot cam, rated at 495 hp, or LS3 long block with ASA cam rated at 525, have heard of tuning issues on both of these with hot cam and ASA cam, I would choose the stock cam version and it it wasn’t enough, down the road upgrade to a cam that suits the car it’s in.

Early 6.0 lq4 or lq9 should bolt in and accept LS1-LS6 intake and all sensors work with original LS1 harness.

 

Can the 6.0 lq4 / lq9 be bored out?

 

Scoggin Dickey sold/ possibly still sells a LQ4/LQ9 block bored to LS3, as a short block, it was basically iron LS3 short block set up for 24 tooth reluctor.

So yes, it appears those blocks can be bored out to LS3 bore size.

 

https://sdparts.com/i-24120757-sdpc-...ort-block.html

I requested price 05/08/2019 for this setup, back then no price was listed.

At the time I was quoted $2200.00, wish I had bought but didn’t have the extra $$.

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CONTACT REQUEST #692306

Mike
05/07/2019 02:19PM

I was wondering how much this short block is, thank you.

Chris @ Scoggin Dickey Parts Center
05/08/2019 08:07AM

2200.00”

 

I believe Texas speed uses the 5.3 aluminum block, bored to a 383. But don’t quote me on that, call them for info.